The GeForce GTX 480 is the first of Nvidia's new Fermi cards that we had the pleasure of playing with and it's one molten beast of a graphics card. In our benchmarks it has regularly hit the 90°C mark and took a layer or two of skin off our unprotected fingers.
Its little brother, the GTX 470 is a far more sedate fella, in heat terms at least. So ripe for a bit of judicious overclocking then?
In our review the GTX 470 proved itself to be an awfully impressive card, capably outperforming the vanilla Radeon HD 5870 that it has been directly pitched up against in almost every benchmark available.
Even at full load though the cutdown GF 100 GPU inside doesn't reach anywhere near the heat of the faster GTX 480. That may be down to a more sensible fan profile management in the drivers than on the bigger card. Just don't expect it to be quiet runner when it's really making an effort in the cooling stakes.Why overclock the GTX 470?
With AMD timing the release of its overclocked, and, optionally DRAM heavier, HD 5870s to coincide with the release of Nvidia's more affordable Fermi card, you might still need a bit of extra pace from your GTX 470 in order to maintain that performance lead.
And this is where we come in, as we've spent some time assessing just how much we can get out of this, the reference design, before it falls over and melts silicon juice all over our beloved test rig. We've scorched our fingers, now you can too.
Obviously it's worth stating that we will accept no responsibility at all if you manage to irrevocably b0rk your brand new, £320 graphics card should you decide to follow these instructions. Overclocking can be a harsh and dangerous world at times. Though today's silicon is fairly robust, and if you're patient and take your time to find the performance sweet spot of your GPU, there is only a little risk to your card, but there is definitely still a risk. Consider yourself warned.
So without further ado, let's crank the air-conditioning up to full, get the fire extinguishers at the ready and set to tweaking the nuts off of Nvidia's latest graphics card.
1. The first thing you need to do is make sure you've got the latest Nvidia drivers for your card. Head to www.nvidia.co.uk and hit the Download Drivers link to find them.
2. Now, to effectively overclock either of the latest Fermi cards you'll have to pick up the latest version of EVGA's Precision software.
3. We've been big fans of MSI's Afterburner software for overclocking graphics, but EVGA's is the only one at the time of writing with proper access to Nvidia's GPU clocks. Head to www.evga.com/precision for the free download.
As we've said, there is always a risk to your card from overclocking, and hence putting extra stress on the GPU, but you can minimise the danger by taking it very slowly and being methodical in your approach.
Part of the process is testing the card's stability after every step to keep an eye out for early signs, such as graphical artefacts. We use the Heaven 2.0 benchmark as a stress-testing tool as it pushes even the latest cards to their very limit. Head to www.unigine.com/download for the free download.
4. Now it's time to get your hands dirty and start messing with the clocks. Starting with the memory first; increase the clockspeed in small increments, maybe 5 to 10MHz steps, and test for a few minutes after each rise.
Keep going until you begin to see the first signs of graphical artefacting, then step back to the previous setting and test again. Keep rolling back until you're happy the memory clock is stable.
Now move onto the core and shader clocks. In this version these clocks are linked so you only need to raise the shader clocks to up the core clockspeed too.
5. Drop the memory clock back down to its default speed and begin upping the shader clock in the same small increments until you start to see processor artefacting then again roll back until its stable. The types of artefacts you'll see will vary depending on whether it's a memory artefact or a processor artefact.
If it's a memory problem then you'll see it manifest itself as solid blocks of colours and if it's a processor issue you'll see pixel-sized dots appear on-screen or bright flashes. When that happens it's time to stop stressing.
Now you should be able to raise both the clockspeeds together. Stress test at the highest ratings you managed individually then keep stepping back in 5 to 10MHz increments until you achieve a stable overclock. Once you're initially happy you've found the mark then it's time to do some longer stress testing to make sure.
When you're sure, hit the 'Apply at startup' tab on the Precision control panel and you're ready to roll next time you boot. Job done.
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