by Oleg Golubovich
10/11/2006 | 11:49 AM
A few days ago we shared with you our achievements during overclocking of Nvidia GeForce 7600 GS series graphics cards (for details see our article called Extreme Voltmodding of the Nvidia GeForce 7600 GS DDR-2 256MB Reference Graphics Cards). We achieved considerable core frequency growth, but the memory frequency grew up but slightly, and it was the memory frequency that prevented us from progressing further. Our recommendation in that article was to look for GeForce 7600 GS cards with GDDR3 memory. We hoped such memory would be better at overclocking and would provide a bigger performance growth.
And now we’ve got a graphics card with such memory on board. It is Gainward Bliss 7600 GS 256MB Golden Sample.
I think you may be interested in that product and its overclockability. This card will be compared with its potential market opponents, an ordinary GeForce 7600 GS with DDR2 memory and a full-featured GeForce 7600 GT.
Let’s learn more about the Bliss and see if it profits much from its faster memory.
This graphics card comes in a rather large box designed in the new colors of the Gainward brand:
The box contains:
Here’s what the card looks like from its face side:
On the reverse side, there are but few large elements:
The PCB is red, the traditional color of Gainward (of its actual manufacturer Palit Microsystems, to be exact; if you are not in the know, Gainward is one of the trademarks owned by that major graphics card maker). This product has a non-reference design of the PCB (which is, however, used on some other graphics card models, too). The power subsystem elements are all placed near the edge of the card:
The card is cooled by an aluminum cooler with a white casing embellished with the Gainward logo:
The cooling system is fastened with a special lock that allows to remove it in just five seconds without a screwdriver or any other tools.
Yes, it’s handy and practical from a PC integrator’s point of view, but not quite from the user’s or the GPU’s standpoint. The latter finds itself in a heat bag made up by the back-plate with a layer of a porous insulation material. This is not good for the thermal conditions of the GPU not only at overclocking but also at the default frequencies.
The blower proved to be somewhat noisy at its max speed, yet it is anyway far quieter than the reference cooler many manufacturers equip their products with.
There’s a layer of white thermal grease between the cooler and the GPU:
The G73 chip on our sample of the card is dated the 8-th week of 2006.
It’s good the manufacture protected the die against physical damage. By default, there’s no protective frame on Nvidia’s GPUs on latest graphics cards.
Aluminum heatsinks are installed on the memory chips. It was easy to tear them off – they are fastened with thermal glue. It is GDDR3 memory in the progressive BGA-136 packaging, which is a big advantage over DDR2 from an overclocker’s point of view. The chips are made by Infineon and have a fetch time of 2.0 nanoseconds.
Take note that Gainward offers two models of 7600 GS based cards, according to the manufacturer’s website. Both models go under the same name of Bliss 7600 GS 256MB Golden Sample, but the other variety uses another PCB design (which differs from Nvidia’s reference design, too!), is equipped with a passive cooler and 2.5ns DDR2 memory. Make sure you’re purchasing the variety you really want!
There are three connectors on the card: Dual-Link DVI-I, D-Sub and TV-out. To use the card in SLI mode, there is an appropriate onboard connector.
The default frequencies of the Gainward Bliss 7600 GS 256MB Golden Edition are 450/500 (1000) MHz. This is higher by 50MHz (core) and 100 (200) MHz (memory) than the frequencies of the reference GeForce 7600 GS, which are 400/400 (800) MHz.
If you haven’t yet grasped what we’re dealing with, you can refer to our review of the Palit GeForce 7600 GT Sonic and compare the two cards. There’s a minimum of difference (a different memory fetch time, heatsinks on the memory chips and stickers on the PCB). This is in fact a unified PCB the manufacturer can use to release a graphics card with whatever characteristics are necessary.
I guess this is good news for people who think the frequencies of the reference GeForce 7600 GS are too low, but do not have the money or desire to buy a GeForce 7600 GT.
The next section will tell you if I am not overoptimistic.
I could overclock our copy of the Gainward Bliss 7600 GS 256MB Golden Sample graphics card from its default 450/500MHz to 513/816 (1632) MHz!
The GPU frequency growth is above average for a GeForce 7600 GS chip, but as for the memory… I checked out the software. Everything worked correctly and reported that the frequency of 800MHz had been conquered. I removed once again the heatsinks from the Infineon chips to see that all the chips were indeed marked as 2.0ns! To tell you the truth, I hadn’t expected that: without any modification I made the memory work at a frequency higher than that of the senior card, GeForce 7600 GT! The PCB from the senior card must have contributed to that achievement.
But the main reason for such a high frequency growth became clear when I measured the voltages: 1.15V on the GPU, which is normal, and 2.02V on the memory chips (which are rated for a voltage of 1.8V). This is a factory-made volt-mod I have seen on some other products from Palit, particularly on the Palit GeForce 7600 GS Sonic GDDR-3 (a card with the same PCB and with similar characteristics) and Palit 7300 GT Sonic GDDR-3.
This good overclocking attempt shouldn’t stop us from getting further, though.
The Gainward Bliss 7600 GS 256 MB Golden Sample with GDDR3 is an exact copy of the earlier-tested Palit 7600 GT Sonic, so it can be volt-modded in the same way. I want to remind you once again that Gainward offers a Bliss 7600 GS 256 MB Golden Sample with DDR2 memory and with a different PCB design – this version of the card can’t be volt-modded using our method.
To check out the overclockability of the card I replaced its native cooler with a liquid cooling system that consisted of a Revoltec water-block (it is a CPU water-block but I had remade it so that it could be installed on GPUs), an external 600lph Eheim pump, and an Airplex EVO 360 radiator with three low-speed Aerocool Turbine 3000 fans. The liquid cooling system worked only for the graphics card during the test. To generally improve the thermal conditions of the card, a 120mm fan was set to blow at the reverse side of its PCB.
The GPU voltage was increased to 1.85V which helped me conquer a frequency of 753MHz. The graphics card could work at higher frequencies, too, but with occasional hang-ups and freezes. The memory chips worked at 835MHz after their voltage was increased to 2.1V, but it was problematic to use it for long under such conditions. The part of the PCB with the power elements became very hot; the GDDR3 memory chips weren’t much cooler, either. I didn’t have normal memory heatsinks at hand, and the fan didn’t help much, so I removed the volt-mod and stopped at 816MHz with the 2.02V voltage as had been set originally by the manufacturer.
In our previous articles we wrote that the so-called delta modification (a reduction of the frequency of one of the GPU subunits to increase the frequency of other subunits on Nvidia’s new GeForce 7 series graphics cards) is a way to get a couple of extra frames per second in your favorite game.
Now I’m going to tell you what exactly and how can be changed and what practical gains it may give you.
First of all, you should know that all the GPU subunits work at the same frequency on new graphics cards, but it is the geometric subunit that becomes the main limiting factor at overclocking. By lowering its frequency in the BIOS relative to the other two subunits (raster operators and shader processors), it is possible to lift up the max frequency the GPU can work at.
We need a fresh version of the nvflash utility that recognizes your graphics card and the Nvidia BIOS Modifier, a utility to change the settings written into the BIOS of graphics cards based on Nvidia’s chips.
You copy nvflash on a boot diskette, reboot and save the original BIOS (type “nvflash –b filename.rom” into the command line).
To modify the delta, open the BIOS image with the Nvidia BIOS Modifier and select the desired negative delta (or positive if you want to make the GPU non-overclockable :)) on the Performance Table tab:
Save the modified BIOS on the diskette, reboot and type in “nvflash –f modified.rom -4 -5 -6”. That’s all! The optimal value of the delta must be found out by a cut-and-try method.
I set the delta at -85MHz for my Gainward Bliss 7600 GS 256 MB Golden Sample. This helped increase the frequency of the shader processors and raster operators to 838MHz. The vertex processors worked at 753MHz. This can be described with the formula 753/838/838 (geometric/shader/ROP)/816 (1632) MHz.
I benchmarked the graphics card in this mode to evaluate the performance gain from such a modification.
To check out the result of the modifications described in the previous sections, I used an open testbed configured like follows:
The CPU was clocked at 2800MHz (350x8) at 1.6V voltage. The memory worked as DDR-133 at a clock rate of 233MHz with 2-2-2-5-1T timings and a voltage of 3.4V.
The testbed ran Windows XP SP1. I overclocked the graphics card by means of RivaTuner 2.0 RC16.
The graphics card driver was ForceWare 91.31. I left the default performance/quality ratio and didn’t use anisotropic filtering or FSAA.
The following benchmarks were used:
Graphics cards of only one class are included into the tests, so I ran all the benchmarks at 1024x768 resolution. The settings in the synthetic benchmarks were left default.
The Gainward Bliss 7600 GS 256MB was tested in the following modes:
I also tested an XFX GeForce 7600 GT 256MB (it is pre-overclocked by the manufacturer to 570/725 (1450) MHz) and an EVGA e-GeForce 7600 GS 256MB (400/400 (800) MHz, DDR2 memory) for the comparison’s sake. This will give us a clear understanding of what can be achieved with the Gainward card.
The diagrams show that at the default frequencies the reviewed graphics card is a little ahead of the GeForce 7600 GS with the reference frequencies of 400/400 (800) MHz, but after its frequencies are increased to the maximum – without any modifications even – it almost overtakes the 7600 GT! We didn’t have such a result even when overclocking an EVGA e-GeForce 7600 GS 256MB to its highest clock rates. Here, you can get a tremendous performance boost without much effort. The volt-mod makes a candy out of the Gainward Bliss 7600 GS 256MB: a 50% growth in frequencies as well as in performance! What’s remarkable, the increase of the frequency of the pixel processors and rasterization units by 85MHz relative to the geometric subunit (the so-called delta modification) provides a small but tangible performance gain in real-life applications!
It’s all the same in this popular gaming benchmark. We’re dealing with graphics cards based on the same GPU, so it’s natural that they behave in a similar way.
With the right settings this benchmark can load any of today’s graphics cards to the full. The results suggest that you just have to overclock the tested graphics card. It is ready to yield a colossal performance gain!
The tests we’ve conducted prove the worth of modifying the graphics card’s firmware in order to increase the frequency of some subunits of the G73 chip and to have an appropriate performance growth. The modification process is simple and requires a minimum of effort on the user’s part, so we do recommend it to you.
As for the graphics card I’ve discussed in this review, the Gainward Bliss 7600 GS 256MB Golden Sample doesn’t need much commenting upon. Notwithstanding its seemingly poor memory, this graphics card is actually nothing else but a GeForce 7600 GT with a reduced core voltage, an increased memory voltage and some stickers that try to convince us that it’s a GeForce 7600 GS. I am very pleased with Palit’s product unification: the junior solutions called Sonic (Palit and XpertVision brands) or Golden Sample (Gainward) are almost 100% copies of the senior models and can be overclocked to extremely high frequencies.
I have personally come to the conclusion lately that you should seek for best mainboards among DFI’s LanParty series and for best graphics cards among Palit/Gainward’s Sonic/Golden Sample series (no offence meant to people who stick to products from famous brands). In 2006 Palit has released several superb graphics cards with non-reference PCBs in a row (7900 GT, 7600 GT, 7600 GS and 7300 GT) which offer excellent characteristics at a reasonable price.
Having thoroughly tested the graphics card, I can give the following summary:
The memory voltage is set above the normal value at the factory, but this has both positive and negative effects. On one hand, the thermal conditions for the memory chips are worsened, but on the other hand, the user can overclock the card to the frequencies of the GeForce 7600 GT or whereabouts without any modifications.
So, if you are interested in overclocking and are going to upgrade your graphics card with a GeForce 7600 GT, take a look at the Gainward Bliss 7600 GS 256MB Golden Sample. Sometimes you can get the same or better thing for less money but under a different name!