How to overclock the GTX 570

Nvidia's revamped Fermi core is a wonder. Let's tweak it!

How to overclock the GTX 570

The Nvidia GTX 570 is a graphics card that seems to balance price and performance perfectly. We love it, and you should too.

While you may want the GTX 580, it's unlikely you'll want to hand over almost £400 to own its three billion transistors, 1.5GB of memory and chunky 512 shader processors running at 772MHz. The smart money should be falling on the GTX 570.

Here's a card offering up to 80 per cent of the performance for two-thirds of the price. You still get your three billion transistors, and the best part of 1.3GB of memory, but it's the loss of a single Stream Multi-processor that's the real cost, producing a 480-shader GPU. But the drop in core speed to 732MHz is less of a worry, as we'll see!

The main dilemma is that there are still a few bargain-priced GTX 480 cards around - at the time of writing has the GTX 480 for a mere £155. However, the reduced noise levels and lower power-consumption of the newer card tip the balance. Only the new AMD Radeon 6950 could put you off snatching up one of these cards, and that's not because it's faster, but because AMD's latest card offers incredible value for money at £220.

Its bigger brother the Radeon HD 6970, meanwhile, fails to impress at the same settings, and is pricier too. This is all before we start cranking the clocks on the GTX 570 to see how high they can go. If it's a good overclocker then it's another reason to stick a stake in the green ground of Nvidia.

How to overclock the GTX 570

step 1

1. We're running a standard Nvidia referenced card; this is good and bad. It's good because it offers a perfect example of what you can expect from most production cards. A lot of the first generation of cards will borrow from this design wholesale, so they can be knocked out as quickly as possible with slight tweaks to clocks and coolers.

It's bad because it omits any possible OC tweaks, primarily access to the core voltage and the new power monitoring hardware Nvidia has introduced on the 5000 range.

step 2

2. "What's this?" we hear you cry. It's similar to the system AMD introduced on the R5000 range, with the PCB having the temperature and power load on each 12v rail monitored by dedicated integrated circuits.

The idea is the driver can monitor the card under stress conditions and throttle back the clock to return the card to a 'safe' power envelope. Importantly, a 'stress' condition only applies to apps selected by Nvidia and so far those are Furmark v1.8 and OverClocking Check Tool (OCCT ).

step 3

3. We find it an odd thing to do but knowing it's there helps you choose the right software to stress the card. It's probably only going to really affect nitrogen freaks and as it so far doesn't affect any games we're safe and sound. The system is optional, so look for cards that enable you to turn it off if you're the type of person who seriously overclocks their system.

The base clock for the GTX 570 is made up of a core of 732MHz - a fixed shader clock of double that at 1,464MHz - and a memory clock at 1,900MHz. Interestingly, before we knew the above, Furmark was running stably at upwards of 850MHz but this didn't fly in any games.

step 4

4. Once we knew, retesting produced a stable overclock at 809MHz for the core and 2002MHz on the memory, bumping the raw clock speeds past those of a full-blown GTX 580! We were a little disappointed in the memory but often this is the case, as it's usually more sensitive to timings.

However it's still a five per cent increase: put this alongside the more impressive 10 per cent jump in Core speed aka 77MHz and it's a GTX 580 matching combination.

step 5

5. When it comes to real-world results this ends up being a rough 10 per cent increase in frame rates. See 'Technical Analysis' for full details, but the Heaven Benchmark saw the smallest increase and is perhaps the least relevant beyond being a good stress-test, increasing just 3fps.

Lost Planet 2 had a solid ten per cent increase moving from 45.5fps to 50.5fps, though the majority of this was within the final benchmark segment jumping 7fps. The same was seen for Just Cause 2.

Technical Analysis

gpu oc

We ran all the benchmarks at 1,920 x 1,080 with 4x AA and the highest detail modes available. We're quite happy with the core speed increase, as it's running faster than a GTX 580. We expect more could be tweaked out of the memory but we're opting for stability over the small FPS increase it might win you.

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