Is it worth upgrading your old PC for gaming?

31st Jul 2011 | 07:00

Is it worth upgrading your old PC for gaming?

We benchmark old vs new to see if upgrading makes sense

Is it worth upgrading your old PC?

Old PCs can be found everywhere. There are millions of them out there, languishing under beds and at the back of cupboards slowly collecting dust. The poor things, it seems such a shame.

One of the big advantages of the PC is that you can upgrade easily - or so it's sold by the industry at large. Surely you can take an old machine and, by adding extra kit here and there, turn it back into something worthwhile? What should you upgrade first? Can you just throw a half-decent graphics card into an old rig and make something of it? Can cast-off PCs be made back into useful members of the gaming community?

Now, enter our base system on which we'll be experimenting. From the dusty recesses of the office, we unearthed a rather neglected desktop. Inside, we had a 2.11GHz AMD Sempron chip coupled to a 512MB Sapphire HD 5550 graphics card and 1GB of RAM, all plugged into a Biostar MCP6P-M2 board and running Windows XP from a 160GB IDE drive.

Even in its day it wouldn't have turned heads, but now it's almost repugnant. Basically, it's a two-year-old budget system. It's still OK if you just want to run some boring old productivity stuff, but it struggles to render recent games at… well… any settings, really.

Given the pick of the office's not inconsiderable pile of hardware, we tested various upgrades to see what made a difference and what didn't. Where are the bottlenecks in the performance, and how easy are they to fix? It turned out to be a bit more difficult than we imagined…

The latest 3D games naturally lean heavily on the graphics subsystem. Very heavily. So all you need to do to turn a mediocre has-been into a gaming powerhouse is add a decent card, right? Bish-bosh, job done. Our base system's Sapphire HD 5550 card is decent enough in its own way, and would be perfectly happy if you stuck to playing around on the desktop, but once you start getting all three-dimensional it begins to fall flat on its pixelated face.

Our suite of games benchmarks revealed a very sluggish system by anyone's standards - and it's no fun playing games that you know can look a whole lot better.

Graphics card upgrade

First, we tried a Radeon HD 5850. Not quite the cutting edge of graphical goodness, but it's a capable card nevertheless.


We tracked down a 1GB Sapphire 5850 Xtreme, retailing for around £100, at which price you can't complain. It required a 6-pin power connector, which our PSU had, and it's not too big physically, either. Fitting the card was easy, drivers installed, benchmarks away and…

The results were most disappointing. The 3DMark06 benchmark showed an improvement of less than 6 per cent, and the game benchmarks didn't fare much better. World in Conflict did manage a decent boost, getting on for double the frames. However, both Far Cry 2 and Lost Planet 2 merely added a frame or two, which isn't quite what you might hope for, what with your wallet being £100 lighter.

Heaven's complete reliance on graphics hardware did at least show us where that money had gone, because the score we garnered from it nearly doubled. Hurrah! Being impressed by artificial benchmarks is all well and good, but what we didn't get in this instance is any decent increase in actual game speeds. Boo.

Time, then, to get a bigger gun. Doubling the budget, we dropped AMD's Radeon HD 6950 in place, which is quite a hefty piece of hardware - literally and metaphorically. At 270mm long, it proved a tight squeeze, but our erstwhile case could take it thanks to the lack of drive bays at the bottom of the machine. It's something to check before you drop cash on a similar upgrade, though, as many older cases weren't designed to handle such beasts.

Power up

After fitting the extra firepower, we fired up the benchmarks and, once again, were completely unimpressed. This time we'd spent twice as much money, only to be more disappointed.

3DMark06 and Heaven 2.5 actually went backwards a bit and the games themselves weren't much happier. All in all, our new £200 upgrade was rubbish. To be fair to the HD 6950, it does scale much better than the 5850 did, something we saw by cranking up the resolutions. And, of course, we have a card designed for a 64-bit OS and drivers, running on a 32-bit system - which didn't help either way.

What we've proved here is that a powerful, and expensive, graphics card isn't the magic bullet you might think. There's a hefty bottleneck at play here, and that bottleneck is the processor. Our 2.11GHz Sempron simply can't feed the graphics card fast enough.

Heaven shows that the cards are doing their thing, but the rest of the system isn't up to it. Spending £100 on a mid-range job is hardly recommended, and spending more is bordering on lunacy. The only advantage in a proper high-power card is that you can easily move it to another system later, so it's not money completely wasted.

A quick look through the motherboard specification also revealed that our base system is running PCIe version 1.1, while everybody and his pixel-pushing dog is sporting version 2.0. This is another reason for our upgrades failing to impress.

It's not quite as bad as you might think, though, because the accepted wisdom is that the PCIe bus is so wide that bottlenecks elsewhere are more important.

Just to prove the point, here are the numbers that matter: PCIe 1.0 and 1.1 shift 250MB/s per lane, in theory. Actually, it fluctuates a bit and (what with overheads and so forth) you really get somewhere between 150 and 190MB/s, which is a maximum of a tad over 3,000MB/s on a 16-lane card - still healthy stuff.

PCIe 2.0 doubles that, exactly, by doubling the base clock. Running on the older PCIe spec will have cost a few frames per second on our benchmarks, which we can ill afford to drop at these low rates. No matter what is says in the adverts or on the back of the box, a sexy graphics card on its own can't perform miracles. Time to change tactics.

Tech labs

All these benchmarks are running under DX9, because we're still chugging along under Windows XP. Since we've changed only the graphics card, we've just quoted benchmarks that will show an improvement.

What we've proved is that just throwing money at the graphics card isn't the answer. The HD 6950 even manages to go backwards (which we put down to the 32-bit drivers). You've been warned: putting a decent graphics card in something too old is a profitless exercise.

GPU bench 1

GPU bench 2

RAM and CPU upgrade


Throwing decent graphics cards at our test case has proved itself to be a bit of a failure, so it's time to look again at what else we can improve. One easy, and hopefully obvious, solution is to throw some more memory at the rig.

There are two DIMM slots on the motherboard, but only one of the slots is populated, giving us 1GB system memory; paltry stuff. An extra 1GB stick will set us back only about £12, too. It may not make a huge difference to benchmarks - in fact, we're a little surprised it made any.

Where the extra RAM does show is during more general use, fiddling around on the desktop, loading files and whatnot. Windows is a greedy fellow and giving it twice as much space to roam means less swap file action and fewer annoying pauses. For the price of a pint and some fish and chips, you can't complain.

Next, we come to the processor. This is what was holding back the graphics card, so we decided to upgrade to the fastest chip the board could handle. It proved a frustrating business.

As we dipped into the secret drawer of processors and tried fitting a few, we found that the best the motherboard would take was an ancient Athlon 64 3800+. An improvement over the Sempron, sure, but hardly a huge leap forward. It has only one core, for a start.

Still, the Athlon is lovely and cheap, and if you can find one new on sale, it'll set you back only about £19 (we checked online and had some available).

The benchmarks showed that we did indeed have more mathematical power. Cinebench and X264, both straight tests of number-mangling prowess, proved it. Though not that much more, it must be said.

World in Conflict was particularly pleased with the new processor, as we anticipated from the more processor-orientated game. Far Cry 2 and Lost Planet 2, meanwhile, were much less impressed, and the Heaven benchmark didn't budge, which shows how good it is at singling out the graphics card for testing. For under 20 quid, you can't really gripe - our machine is better.

We've hardly created a gaming powerhouse, though, just a machine that's slightly less rubbish than the one we started out with.

The next step in the process is clear: we return to our graphics cards and see if the extra oomph helps get the balance back. We fitted our £100 HD 5850 with the new processor and, well, we got pretty much what we expected. A moderate improvement, but hardly worth the money.

Our new graphics card still didn't have a match in the processor. The Heaven 2.5 benchmark showed that we had all that graphics power on board, but it wasn't translating into good gaming. Although we were closer to our goal, at a total cost of £131 it didn't look like good value at all.

Getting the balance right between graphics and processor is key to upgrading old rigs. However, before we start to get serious and upgrade the motherboard, which desperately needs doing, we take a different tack again.

Tech labs

Adding an extra GB of memory does little to our tests, but Windows did enjoy it. Changing over to an Athlon 64 3800+ processor helped for CPU-intensive operations, and showed that graphics and processor work in tandem.

However, we still needed to upgrade the graphics card to see decent improvements. The HD 5850 now squeezed out a few more frames per second with its new partner than it managed on its own, but it was still being held back.

CPU bench 1

CPU bench 2

Windows upgrade


Our faithful old machine was running Windows XP, which is now positively archaic. Is running a 32-bit system holding us back? You may well be upgrading older machines with Windows 7 anyway, but what will it do for your game power?

While we were at it, we decided to upgrade the storage as well. The 160GB IDE drive was a little small and we had nice SATA connectors on the motherboard doing nothing. What could an SSD do? Blazing speed, obviously - or so we thought.

Although the BIOS appeared happy, Windows was not. It simply wouldn't boot from an SSD. After initially suspecting the drives, we realised that it was the motherboard again and its lack of AHCI support. There was nothing we could do about that, so it was back to regular HDDs.

We added a SATA-based 1.5TB Seagate Barracuda, and put a fresh copy of Windows 7 on it. Lastly, we threw two 2GB memory sticks on the board. Well, why not?

Upgrading Windows cost about £75, the hard drive was £65 and the memory another £30 or so, bringing the cost of this exercise to £170, a not inconsiderable sum. And possibly more than the base rig was worth even new…

Direct results

Upgrading Windows for gaming purposes has its ups and downs. Yes, you get DX10 and DX11, which means you have all the latest shiny effects and 64-bit code. Plus you get access to a lot more system RAM. If you've got 64-bit versions of software, then you can now run them - witness Cinebench, and the little bit of extra speed it finds.

It's just as well, because the 32-bit version we used on XP actually runs slower on Windows 7. We could now run our tests under DX10 and DX11. Unfortunately, if the quest is all about speed then this is no good thing. It's far more demanding and the scores subsequently went down.

However, it turned out that switching back to the DX9 versions of the benchmarks didn't help, either. Sometimes you just can't win.

We had one last test to consider - to see what moving to a factory-fresh SATA drive and 64-bit drivers had done for our hard drive: wonders, as it transpired. We doubled the average read and write data rate, according to ATTO (though this doesn't show in the games benchmarks, of course).

Did this mean Windows would boot faster? No. In fact, it was about 15 seconds slower - now a full minute. Sometimes you could just slap Windows… Our upgraded machine at least looked modern, and it gained access to all the latest software.

In general use, the hard drive and extra memory helped to make it more responsive, but we've still not really addressed the main problem of poor gaming performance. Windows isn't a bottleneck here, then. No matter how attached you are to XP, or to DX9's slight speed edge, you can't hold back the march of time. You've got to upgrade Windows eventually, and while it'll give little improvements here and there, it'll do nothing for gaming other than frustrate you when you try to run DX10 and DX11 stuff.

Looking for the performance upgrade, then, we don't think it's money well spent here, either.

Tech labs

Upgrading Windows isn't cheap, which might explain why Microsoft has so much money. Our upgrade from XP means that 64-bit software and DX10 and DX11 are ours. What it doesn't do is make our system any faster, although the desktop looks nice and modern.

As ever, Windows gets more demanding. This is no performance upgrade, and if anything it only highlights the inadequacies of our box. It isn't always very good at running 32-bit software, so you might find that things actually go backwards. Still, our hard drive upgrade is a nice one; £65 brings an almost 10-fold increase in storage, as well as a doubling of the data rate.

Win bench 1

Win bench 2

Motherboard and CPU upgrade


Now then, time to get serious. All we've learned from our mucking about upgrading this and that is that what we really need is to fit a decent processor - and our motherboard is too old for that. So it's time to change the board.

Since this is a biggish job, there's no sense in aiming too low. We went straight for a six-core Phenom II 1090T. At about £150 a pop, they're not cheap, but we'd finally have oodles of six-core power. Our new board was an Asus M4A89GTD Pro, about £90 worth and capable of interesting overclocking experiments. On top of this, we'd need new memory: a pair of 2GB DDR3 sticks added £32-ish. All this brings the bill to about £250 - about half the cost of a modest new PC.

Remember, we're still running everything under XP with a pedestrian 512MB graphics card. Heaven 2.5 once more refuses to budge. It doesn't matter how much processing power you throw onto the board, it's all about the graphics card here.

3DMark06, which is much more skewed to CPU power, at last gets a decent hit, nearly doubling. The two CPU benchmarks, as you might have guessed, go ballistic. It all goes to show just how fast processor development is; a decent modern chip will absolutely slaughter the old guard. The machine also feels completely different at the desktop, nice and responsive.

Right, we've spent £250 and started to get interesting scores, but now our system is unbalanced again. Where once it needed processing power to match the card, now it desperately needs graphical power. So it's back to our HD 5850 and 6950 cards and more furious benchmarking to see whether we can at last get some decent chuffin' results. Which we can.

The HD 5850 finally has a chance to run and we have, ladies and gentlemen, boys and girls, decent playable speeds. The 3DMark06 benchmark nearly doubles again and Heaven more than doubles.

The game benchmarks start responding, too. At last, our upgrade candidate is a games machine, which is just as well as we've now spent £350 and it's still running an obsolete OS on an IDE hard drive.

Smart money

Spending another ton to move to an HD 6950 doesn't repeat the trick, though. Since we're sticking to our original resolutions of 1,280x1,024, it doesn't have a chance to flex its GPU muscles. At these more sedate dimensions, and with no 64-bit drivers, it's not much better than its older cousin.

Again, spending the extra here would be something of a waste, which did surprise us a little - we expected more for our money now it was on a decent board.

The law of diminishing returns is in full effect in the world of graphics cards, and those last few frames get costly. We were really tempted to combine the Windows and drive upgrades with the processor and motherboard and graphics card upgrades to see what the result would be. At least, we were until we started adding up the figures and realised that way madness lay.

At this point, all that would have been left of our original box would be the case, power supply and optical drive, and our upgrade would have set us back about £500. This isn't really an upgrade, it's building a whole new rig. Time to calm down and think again.

Upgrading is one of the PC's great advantages, but it's a fast-moving field and machines are quickly left behind. To be realistic, after more than a couple of modest upgrades of an ageing computer, it's time to stop and think carefully about what you want the machine to do. It's possible to waste quite a lot of money on something that's never really going to perform well enough to justify the subsequent lightness of your wallet.

Tech labs

This is the big upgrade. It's also the most expensive, but it doesn't half make a difference. Suddenly, our tired old rig has a spring in its step. Although it needs a new graphics card to carry the extra power right through to the game frame rates, we're at last in decent, playable territory.

We jolly well should be, as it's cost £350 to change the board, chip and memory, and add an HD 5850. Notice that stretching another £100 to the 6950 again proves to be a waste, at these resolutions anyway (1,280x1,024).

Mobo bench 1

Mobo bench 2


So we've answered our original question. Yes, you can turn an old dog into a gaming machine - of course you can. You just can't do it without spending rather a lot of money and replacing nearly everything, making your old PC a bit of a Trigger's Broom (or Ship of Theseus, if you're more classically minded).

Once upon a time, you could beat the system by building rigs out of bits and it would be cheaper. Even if you had only a couple of major components, it was worth buying the rest separately. Those days are long gone.

Today, margins are tight, competition fierce and progress rapid. You'll rarely put together a decent system out of separates and save money. The same goes for any major upgrading. The balance between processor and graphics card is all-important: too much either way is wasted effort.

And watch those resolutions, too. If you don't run a big monitor then many high-power cards aren't as attractive as they think they are. For instance, witness our 5850 and 6950 scores with the Phenom 1090T at 1,280x1,024 - is that really worth £100 to you?

The PC is made of parts, but works as a whole, and you need to upgrade it with this in mind. The cost of fitting fast, modern kit is dissipated unless all of the sub-systems can cope. This effectively means that any serious upgrade means a new board, chip, graphics and RAM. And at this point you need to consider costs carefully.

Looking again at our original test system, all we can really recommend is adding another GB of RAM and hunting down an Athlon 64 chip. This would cost a reasonable £31 and gives a little boost all round - nothing spectacular, but the desktop feels much more lively and you get a few frames a second more here and there.

Maybe scouring other piles of old hardware or eBay for a better graphics card would be worth it, but getting serious about upgrading it proved to be an expensive and frustrating experiment.

Drive time

The only upgrade that really worked was the hard drive. Switching to a modern SATA drive had an immediate effect and, although not speeding up games as such, made everything feel more lively. You can never have too much storage, either, and drives are easy to transfer between systems.

You can get a lovely, all-shiny, all-new, all-sorted-out proper games rig for £750 (take a look at Chillblast's Fusion Rocket). You'll get a nice new version of Windows, too, plus big, fast drives, a new keyboard that isn't full of crumbs, and a new mouse and all the rest.

It pains us to say it, but it's worth saving up and getting a new box if you're more than a couple of years behind the curve. It's tempting to think that you can upgrade some faithful old PC you found hidden away somewhere into a games box, but once you've passed a certain point it's time to take the old fellow out for a long walk, with a spade in one hand and a shotgun in the other.


First published in PC Format Issue 254

Liked this? Then check out The best PC upgrades for gamers

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