The rear of the card is as you would expect, the only prominent feature being the retaining bracket for the heatsink. The attached fan is very quiet and at full speed is not audible over the system fans.
I am only briefly going to cover the actual process to overclock your card as there are numerous guides on how to do this and there are always people willing to help you here on AOA..
Basically overclocking your card involves either installing coolbits.reg which is available here on AOA, or using modified drives such as those from Tweaks 'r Us which have this feature pre-enabled and then enabling manual overclocking and moving the core slider up 5Mhz at a time, running the “test settings” and when it reaches a point where it fails the test back off around 10MHz and benchmark to ensure stability. Once you have found your optimum core speed then repeat the process with your memory until you have the best overclock attainable.
The core should nearly always be overclocked first as your maximum core clock may not always be achievable when your memory is maxed out, in most cases core speed is more beneficial than memory speed.
In my case I reached 580MHz on the core and 1450MHz on the memory which is a 29% overclock on the core and around 10% on the memory. Any card which allows a core overclock of more than a quarter straight out of the box can't be ignored.
Neither I or AOA take any responsibility for any damage or loss that may be caused through overclocking or modification of your equipment, you perform it at your own risk, however if you experience problems then we are happy to try and help you.
With that aside, let's begin.
The non-standard board design on Palit (and some other) 7900GS cards means that no conductive ink methods are necessary to increase the core voltage to the card, other brands can use modified BIOSes to increase the core voltage to 1.3v in 3D mode, on this card we can change it to suit our needs.
The resistor highlighted in the picture (just adjacent to the power input -Ed) is rated at about 620ohms, reducing the resistance of this will increase the core voltage of the card and hence increase the overclocking potential, what we have to bear in mind is that an increase in voltage is going to cause an increase in heat which the cards heatsink will have to be able to remove quick enough to prevent the card from overheating, artefacting or even failing entirely.
All you need to do to reduce the resistance is to get a sharp pencil and draw a gentle line from one end of the resistor to the other, using a multimeter check after each stoke to see how you are doing, when you reach your desired resistance then you can replace your card and see how much your overclocking potential increases, I recommend aiming to reduce it by 10ohms at a time, this way you can check temperatures each time and not overheat your card.
Through experimentation I discovered that reducing the resistance of the component to 600ohms which is around the 1.3v mark was the optimal level (no major increase in temperature but increased overclocking potential).
This is more than a 36% increase over the stock speed of the card, I discovered that by lowering the resistance to 550ohms (resulting in around 1.45v) I was able to achieve and overclock of 650MHz a staggering 45% overclock, however at this voltage temperature increased quickly and it was only stable for around 60 mins, however if you are willing to mod the heatsink to fit ram-sinks onto the card or to improve ventilation across the rest of the card then it is quite achievable.
It is worth noting that around the 650MHz mark I started to find the overall system was CPU limited so if you have a lower spec CPU than what was used in the test then it may not be worth aiming that high.
I have run a set of benchmarks to highlight the stock performance of the card and how much difference overclocking makes to benchmarking results, these increases can be roughly translated into real-life gaming performance.
The Test System
Athlon 64 3200+ skt939 @2500MHz(watercooled).
MSI K8N Neo4-F.
2048MB Corsair DDR500 3-4-4-8.
2x40GB Barracuda (RAID 0).
Palit 7900GS 256MB.
SB Audigy 2 ZS
Hiper 525W PSU.
Windows XP Home SP2
TRU XG-92.91 Nvidia drivers.
Aquamark 3
A rather old benchmark now but it often useful to help show if a system is being CPU limited and a good comparison for comparing against older cards.
An average of 83,611 at stock speed and 87229 overclocked giving a 4.3% increase.
3DMARK03
An older benchmark but still very popular in comparisons with other cards.
An average of 15723 at stock speed and 18426 overclocked giving a 17.2% increase.
3DMARK05
A very good benchmark for comparing relative performance at a level that most recent games are running at.
An average of 7283 at stock speed and 8786 overclocked giving a 20.6% increase.
3DMARK06
The most up to date benchmark and the newer, better computers come into their own here, cards which are not SM3.0 compliant will fall by the wayside.
An average of 3778 at stock speeds and 4464 overclocked giving an 18.2% increase.
Battlefield 2
To give a better idea of the real-life performance of this card compared to others, I have tested its performance in one of the most popular current games Battlefield 2 by Electronic Arts, the results were taken using FRAPS (a utility to measure current and average framerate during a game) over a period of 5 minutes on Strike at Karkand one of the best maps at a resolution of 1280x1024 with all settings on high except “effects” and 4xAA.
Average Framerates:
Stock: 88.4 FPS
Overclocked: 93.1 FPS
Only a 5% increase in speed, which is not too surprising being that BF2 is capped at 100fps so the points where the card is not under 100% load and would normally go well above 100fps do not influence the results so much, also some CPU limitation may be coming into effect, this is reflected in the Aquamark 3 results previously.
In terms of price:performance ratio this card is untouchable, the 7900GTO comes very close but at less than £120 and with overclocked performance similar to that of a 7900GT the 7900GS has found place in the market that was waiting to be filled and filled it perfectly, as far as I am concerned I cannot find a fault with this card at its current price.
With the performance to keep up with the big guns and the cost and noise level of a much lesser card I think the 7900GS is going to be the leader of the high performance, low cost card arena for some time.
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