Everyone likes to know how far they can expect to be able to overclock a certain graphics card. This is especially true if they are in the market to buy one. Most people will attempt an un-modified overclock first and this is just what I’ve done here. So exactly how much further did I manage to take it?

How I Overclocked it
The Gigabyte 1GB 4850 graphics card comes with an application called ‘Gigabyte Gamer HUD’ and this will allow you to overclock the card. It’s also possible to overclock this card using the ATI catalyst control center driver software. The result should be much the same with either software. Gamer HUD will allow an overclock up to 750 MHz on the core clock and 1198 on the memory clock, this is quite reasonable for a bundled application. CCC also offers these same clock speeds under the ‘Overdrive’ option of the advanced section. These values are the ‘locked’ maximums stated in the graphics card’s BIOS and this is why both applications offer the same maximum.

The HUD software looks a bit messy with its transparency effects but it does actually work well and I can recommend using it. It’ll keep your overclock at next boot up too while allowing you to click the notification area icon to open it up for adjustments.

How far did it go?
It’s important to stress that this card is actually overclocked already out of the box. The standard ATI 4850 spec is for a core clock of 625 MHz with a memory clock of 993 MHz. The memory is the same on the standard Gigabyte card but the core has been increased 12% to 700 MHz. The advantage of a pre-overclocked card is that it’s overclocked for maximum performance yet retains its warranty. You can also be absolutely sure before buying it that it will run stably at those speeds, after all if it didn’t you’d just send it back! In the enthusiast forums you will find accounts of people unable to overclock their 4850 to even 700 MHz without modifications.

So I began by overclocking the core. This I finally managed to push up to 745 MHz, not a lot more than the 700 it started at but it pushes it up to more than 100 MHz above the ATI standard for a 4850. The memory unfortunately didn’t do so well and only ran stable at up to 1033 MHz which considering it’s not overclocked out of the box is very disappointing. Many other 4850 users report getting much better memory overclocks than this, whether this is due to the lack of memory heatsinks or not I’ll find out when I get round to putting some on. It could also be due to the larger memory chips not overclocking quite so well, remember the standard cards have 512 MB DDR3 rather than the 1 GB of this Gigabyte card.

The final core overclock is a 6% increase over the Gigabyte’s standard core clock and an 19% increase on the standard ATI core clock of 625. The memory overclock though only equates to an additional 3.5% which as I mentioned is disappointing.

Temperature under Load
The GPU temperature of the 1GB Gigabyte 4850 is pretty low due to the Zalman Heatsink and Fan (HSF) that is fitted. As such you wouldn’t expect a small overclock to increase the temperature much if at all. This is what we see in practice, the GPU temperature remains at much the same as it did before the overclock. Running the FurMark test the GPU hits 68C overclocked.

With temperatures in this range and knowing the kind of temperatures these 4850 cores can be exposed to when fitted with reference coolers, I would suggest that there may be significantly more overclocking head room with an increased voltage. However, with graphics cards that generally means getting the soldering iron out and physically modifying the card which is not for the faint hearted. Something which I’ll aim to do another day.

Performance
This is where the rubber hits the road. What really is the point of overclocking any component if it doesn’t lead to some kind of performance increase? For a true picture of the performance of this graphics card and it’s overclock I’ve compared the standard performance, the overclocked performance and the performance when underclocked to 625 MHz which is the standard clock speed of a reference 4850 card.

ATITool – Spinning cube fps
The first test that I ran is the ATITool spinning cube. This gives a constantly updated average frames per second (fps) value which settles very quickly because the image is always the same. It makes for a very quick benchmark test and it’s a test that is very GPU limited and the CPU is not stressed much at all.

There is a clear increase in performance due to the overclock but it’s not a huge change. The overclock adds an additional 5% which translates to an additional 9% over the reference card. For a 6% overclock over stock and a 19% overclock over reference this is a little disappointing and is probably due to the fact that the memory has barely overclocked at all.

FurMark – Default Settings
The FurMark benchmark test is much the same as the ATITool test, a spinning donut rather than a cube, although it does provides min, ave and max fps values. I run this test with the default settings i.e. the settings that are selected when you first run the program except that I run it in windowed mode.

Again we see increases due to the overclock but not significantly. Much the same as the previous test with the minimum fps increasing by 4% over stock and 9% over reference, the average increasing by 5% over stock and 11% over reference and finally the maximum increasing 5% over stock and 12% over reference.

Futuremark 3DMark03
Next I move on to the futuremark graphics benchmarks. Again this is a freely downloadable benchmark so you can compare your own system directly and to aid in this kind of comparison I use the default settings from the free version.

This is a benchmark that aims to be more like a real game in its requirements of your PC hardware and as such is a better indicator of real gaming performance. Here again the picture is much the same with 4% and 11% over stock and reference respectively.

Futuremark 3DMark05
The 3Dmark05 benchmark follows the same theme as the 03 benchmark its just a bit more current and puts a bit more of a demand on the system.

There’s an even more grim result with 3DMark05 showing just a 2% increase over stock and a 4% increase over reference. Maybe the 4850 is really starting to show itself as memory limited here.

Futuremark 3DMark06
The 3Dmark06 benchmark surprised me a little bit as I had expected it to show an even lesser increase than the 05 version.

It manages to return an equivilent 2% over stock and an improved 6% over the reference clocks. Still the performance increase is nothing to shout about!

Half Life 2 and Counter Strike Source
These two benchmarks are the ‘video stress’ tests that are available from the main menus of Half Life 2: Lost Coast and Counter Strike:Source. These are benchmarks of actual games and both use the source game engine so these tests should show a more acurate view of the overclock.

The Half Life 2 Lost Coast benchmark scaled particularly badly with this overclock. It did see frame rate increases but they were so poor that they translate to 0% however you view the figures, the Counter Strike Source benchmark does little better but we do see 2% over stock and 3% over reference.

Grand Theft Auto 4
Usually I would include Track Mania Nations as a benchmark because it’s a graphically challenging game and it’s free which makes it easy for anyone to compare against. However, I cannot get it to run on Vista64 with this graphics card. So I’ve used the internal benchmark in GTA4 as a final comparison. I’ve used the autoconfig settings for my system at 1680 x 1050 resolution.

I was mildly surprised by this result as the overclock gained me an additional 3% over the stock clocks which is an additional 7% over the reference clocks. For such a PC intensive game I hadn’t expected anything at all really.

Conclusion
The overclock only provided an additional 4% average increase across all benchmarks which is disappointing. It does however, relate to an additional 8% over the reference clocks which is better. It won’t make an unplayable game suddenly playable but it is an overclock that can be performed without any physical modification to the card so you may as well have it. It can also be set in the Gigabyte HUD program to overclock on windows boot, so it doesn’t need resetting each time you reboot and so I’m certainly going to run 24/7 at this overclock.

If you missed my review of the Gigabyte 4850 1GB OC then don’t fear, you can find it just here : Review: Gigabyte HD4850 1Gb pre overclocked – (GV-R485OC-1GH)

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