Overclocking

Overclocking is a valuable tool when looking to get the most out of your graphics solution. Many card manufacturers sell overclocked versions of their cards, often with positive results. A few of the cards we have come with their own factory overclock, but we make a habit of doing our own user-overclocking whenever we can and this review is no exception.

We were able to overclock these cards using Coolbits for the NVIDIA cards, and a handy program called ATI Tool for the ATI cards. ATI tool has a built in 3D view of a rotating fuzzy cube to test the stability of the card while overclocking on the fly. We use this to get our initial overclocks, and then follow this test up with repeated game benchmarks to ensure that the card runs stably (i.e. without any graphical tearing or artifacts). Below is a list of the cards and the overclocks we achieved, as well as their factory clock speeds.

GPU Overclocking
Factory Clock User Overclock
ASUS NVIDIA GeForce 7800 GT 420/1240 481/1290
ASUS NVIDIA GeForce 7600 GS 512 400/540 483/596
ASUS NVIDIA GeForce 7600 GS 400/800 442/874
ASUS NVIDIA GeForce 6600 GT 500/1000 561/1070
ASUS ATI Radeon X1600 XT 590/690 624/751
GIGABYTE NVIDIA GeForce 7600 GT 560/700 608/734
GIGABYTE NVIDIA GeForce 7600 GS 450/800 549/890
GIGABYTE NVIDIA GeForce 7300 GT 450/800 474/858
GIGABYTE NVIDIA GeForce 7300 GS 550/800 644/851
GIGABYTE ATI Radeon X1600 PRO 500/400 580/432
GIGABYTE ATI Radeon X1600 XT 590/690 621/706
GIGABYTE ATI Radeon X1300 PRO 600/400 650/409
GIGABYTE ATI Radeon X1300 450/350 610/405
EVGA NVIDIA GeForce 7600 GS 400/800 445/875
Sparkle NVIDIA GeForce 7300 GS 550/532 611/700
Albatron NVIDIA GeForce 7300 GT 400/800 502/884
HIS ATI Radeon X1600 PRO 500/400 597/441
HIS ATI Radeon X1300 PRO 600/400 640/445
MSI NVIDIA GeForce 7600 GS 400/800 441/875
MSI NVIDIA GeForce 7300 GT 350/667 486/830

Heat is always an issue when overclocking, and because we are dealing with silent graphics cards, we took extra care when boosting the clock speeds for these cards. Interestingly, all of these cards were able to be overclocked to some degree and saw a degree of performance increase. Of course some overclocked more than others, and there were a few cards that did notably well for us, as our table shows. In particular, the Gigabyte X1300 got a 160 MHz boost in the core clock resulting in about a 23% boost in Battlefield 2 at 1024x768, making the game much more playable at this resolution. The MSI NX7300 GT also got a high overclock in both the core and memory clock. It appears that in general some of the slower cards like the X1300s and 7300s overclock better than the faster ones, which is ultimately good news for those who are limited to the slower cards because of price.

Once we achieved our overclocks for these cards, we again tested performance in Battlefield 2 and Oblivion to get a general idea of the increase in performance with the new clock speeds. As these are two of the most graphically demanding (and popular) games in our testing, their benchmarks are particularly useful to see how well these cards overclock. Keep in mind, however, that how well a card overclocks will vary even between two cards of the same model and manufacturer, so the clock speeds we achieved with our Gigabyte 7600 GS won't necessarily be what you will see with your Gigabyte 7600 GS.

Battlefield 2 v1.22 Overclocked
800x600 1024x768 1280x1024 1600x1200 Avg. Increase
ASUS 7800 GT Top Silent (481/1290) 60.2 59 58.7 57.5 1.85%
ASUS 7600 GS Silent 512 (483/596) 61.7 56.6 43.8 32.6 11.01%
ASUS 7600 GS Silent (442/874) 60.7 57.9 47.5 36.3 5.33%
ASUS 6600 GT Silencer (561/1070) 59.1 51.4 38.8 30.3 8.66%
ASUS EAX1600 XT Silent (624/751) 61.7 55.3 39.9 29.2 4.96%
GIGABYTE 7600 GT (608/734) 59.7 58.2 57.5 51.1 1.44%
GIGABYTE 7600 GS (549/890) 60.6 56.6 53.4 41.7 7.64%
GIGABYTE 7300 GT (474/858) 67.3 61.2 38.3 28.9 12.60%
GIGABYTE 7300 GS (644/851) 45.3 62.2 23.4 17.1 47.40%
GIGABYTE X1600 PRO (580/432) 61.2 63.2 35.3 25.7 2.28%
GIGABYTE X1600 XT (621/706) 62.2 64.2 39.5 27.7 25.38%
GIGABYTE X1300 PRO (650/409) 47.8 65.2 23.2 16.5 30.95%
GIGABYTE X1300 (610/405) 37.6 66.2 18 12.4 82.61%
EVGA e-GeForce 7600 GS (445/875) 60.7 57.9 47.5 36.3 5.33%
Sparkle 7300 GS Ultra 2 (611/700) 42.3 31.8 21.9 N/A 24.28%
Albatron 7300 GT (488/860) 70.4 55.2 40.2 30.3 22.86%
HIS X1600 PRO (597/441) 61.6 51.2 36.3 26.4 13.79%
HIS X1300 PRO (640/445) 48.1 35.7 23.5 16.8 9.40%
MSI 7600 GS (441/875) 60.6 57.8 47.5 36.3 5.25%
MSI 7300 GT (486/830) 68.4 53.4 39 29.3 34.63%

Oblivion Gate Overclocked
800x600 1024x768 1280x1024 1600x1200 Avg. Increase
ASUS 7800 GT Top Silent (481/1290) 59.7 56.9 47.2 37.5 4.00%
ASUS 7600 GS Silent 512 (483/596) 42.1 32 21.7 16.3 13.32%
ASUS 7600 GS Silent (442/874) 50.7 35.6 25.4 18.5 12.29%
ASUS 6600 GT Silencer (561/1070) 40.6 27.8 19.6 14.9 16.19%
ASUS EAX1600 XT Silent (624/751) 40.2 29.4 20.2 15.5 7.51%
GIGABYTE 7600 GT (608/734) 61.5 53.9 38 27.6 8.83%
GIGABYTE 7600 GS (549/890) 52.4 42.2 28.1 21.8 14.57%
GIGABYTE 7300 GT (474/858) 38.9 29.7 20 14.9 6.79%
GIGABYTE 7300 GS (644/851) 21 16.1 10.7 7 18.06%
GIGABYTE X1600 PRO (580/432) 32.4 25.2 17.4 13.5 10.61%
GIGABYTE X1600 XT (621/706) 38.7 27.7 20.9 15.7 6.11%
GIGABYTE X1300 PRO (650/409) 28 19.2 12.9 9.5 11.53%
GIGABYTE X1300 (610/405) 22.4 16.3 11.2 N/A 34.35%
EVGA e-GeForce 7600 GS (445/875) 50.8 35.7 25.5 18.5 12.54%
Sparkle 7300 GS Ultra 2 (611/700) 19.6 14.5 9.7 N/A 26.05%
Albatron 7300 GT (488/860) 41.2 29.9 22 15.9 19.69%
HIS X1600 PRO (597/441) 35.7 27.1 19.1 13.2 17.44%
HIS X1300 PRO (640/445) 26.5 18.9 13.1 8.5 6.95%
MSI 7600 GS (441/875) 50.6 35.6 25.4 18.5 12.23%
MSI 7300 GT (486/830) 41 30.5 20.4 15.7 37.47%

Now that we have our overclocked performance numbers along side of our factory clocked ones, we can see how well these cards perform overclocked relative to each other. In Battlefield 2, we can see how certain cards that only got borderline-playable framerates at 1600x1200 and 1280x1024 with their factory clock speeds became playable at these resolutions with a bit of overclocking. The MSI NX7300 GT in particular at 1600x1200 gets a 35% increase in frame rate going from 21.7 fps to 29.3 fps. Also, the Gigabyte 7600 GS benefits the most from its overclock to 549 and 890 MHz at 1600x1200 resolution, getting almost a 17% increase in framerate.

In Oblivion, the increases in framerates seem a little more dramatic in the more graphically intensive "Oblivion Gate" benchmark, but we again see a few marked improvements in performance in each benchmark. Again the MSI NX7300 GT and Gigabyte 7600 GS stand out with their performance increases. In this roundup, the Gigabyte 7600 GS sets itself apart from the other three 7600 GS cards (the MSI NX 7600 GS, EVGA e-GeForce 7600 GS, and the ASUS EN7600 GS Silent). Not only is it the only 7600 GS that comes with a factory overclock, but it also manages to achieve the highest user overclock of the four resulting in slightly better overall performance.

Cards Summary and Prices Test Setup
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  • imaheadcase - Thursday, August 31, 2006 - link

    I guess to each his own, i play bf2 on a 19inch CRT monitor at 1024x768. But even if i had a better card i would still prefer lower rez.
  • DerekWilson - Thursday, August 31, 2006 - link

    it's an issue of how games work on the inside ...

    all the objects, shapes, characters, and landscapes are there no matter how you see them. everything is mathematically represented in the software. rendered onto your display is a viewport into the world. this viewport only allows you to see a fixed grid of colors. the color of each pixel is determined by a bunch of factors, but the largest contribution is made by the object that projects onto a particular pixel.

    ... on second thought, this is too hard for me to explain with out a lot of math. lets look at it another way.

    when there's a naked person on tv, they decrease the resolution of the area over the persons naughty bits. this makes it harder to see what's really there because there is a smaller number of large pixels that can only represent one color each. it follows, then, that it would also be harder to shoot the person acurately in said bits.

    I think your preference may be based on your experience with performance at higher resolutions. Responsiveness is necessary for a quality experience in games like bf2. If you get a faster card, I would encourage you to at least try a higher resolution.
  • blckgrffn - Thursday, August 31, 2006 - link

    When it is in stock at newegg, its ~$90, not nearly $140.

    Nat
  • mostlyprudent - Thursday, August 31, 2006 - link

    I would be interested to know how much noise (quantitatively) an actively cooled 7600GS or 7600GT contributes to a system built in a relatively quiet case like an Antec P150. I am familiar with some of the leaf blowers attached to the higher end cards, but wonder how much overall system noise savings you'ld get in the mid-range cards.
  • wilburpan - Thursday, August 31, 2006 - link

    One obvious use for silent video cards would be in an HTPC system, where quiet performance would be a priority. Can't have those noisy computer fans intrude on watching Snakes on a Plane, you know. :@) Anyway, it would have been nice to include some video playback benchmarks to see how these cards can handle playing back a 1080p HDTV signal, or similiar tests.
  • ViRGE - Thursday, August 31, 2006 - link

    Since HDTV is MPEG2, any modern video card should be able to handle a 1080P signal(since this is an either/or case, it either can or can't). The limitations come in to H.264, where the video decode engine may not be clocked high enough to do higher resolution decoding. Unfortunately, I'm not sure there's any 1080 commerical/usable content that would work with Cyberlink/Intervideo's H.264 decoders(the only ones with GPU acceleration), since Quicktime content doesn't work in those.
  • DerekWilson - Thursday, August 31, 2006 - link

    with nvidia, the video decode engine is clocked off the core -- it actually will run better on a card with fewer pipelines and a higher core speed ... iow, the 7600gt is a better video decode graphics card than a 7900gt at default clock speeds.

    a little counter intuitive, but there it is.

    nvidia 7 series parts with a core clock of >450 MHz should have no problem accelerating 1080p decode on players that support purevideo.
  • MontagGG - Thursday, August 31, 2006 - link

    Which of these have HDCP?
  • DerekWilson - Thursday, August 31, 2006 - link

    to my knowledge, none of the cards tested here support hdcp. but I will certainly try to confirm this ...

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