Palit GeForce 7600 GT Sonic Graphics Card: Extreme Voltmodding Guide

Today we are going to introduce to you an excellent solution for the buck – the new GeForce 7600 GT from Palit. It boasts unique design different from the reference and with a little effort can be modified to hit new performance heights. Read more in our detailed review!

by Oleg Golubovich
10/09/2006 | 04:16 PM

Palit, Yuan, Daytona, XpertVision, Gainward… I’m not sure if this list is complete. What does it mean? I guess experienced users who are interested in PC hardware should know that Palit Corporation is today a major graphics card manufacturer and owns all those trademarks. There’s no unanimous opinion about one company having so many brands. On one hand, the user is offered a larger choice, especially since Palit has always offered an appealing price/performance ratio (note that I don’t mention quality here). On the other hand, a carefree user may be enticed into buying a cut-down version of some full-featured model. Such a version may have slower memory, a narrower bus, a simplified PCB, fewer graphics pipelines, etc.

 

Today, I am going to test a Palit GeForce 7600 GT Sonic graphics card. We’ve already written about the 7600 GT on the pages of our site, but it is such a wonderful product that we just can’t stop admiring it. Its excellent performance comes at a lower price, now that the initial excitement has subsided. Graphics card makers are not confined to the reference design with this card, so there have appeared a number of original designs from several companies. The card to be discussed in this review uses a non-reference design of the PCB, too.

Palit GeForce 7600 GT Sonic: Overview

The Palit GeForce 7600 GT Sonic comes in a large and glossy cardboard box embellished with the traditional emblem of that manufacturer, a fairy Chinese girl. She is a lucid indication of the place of origin of the product.

The box is filled with a porous material to protect the card during transportation. A manufacturer’s attention to such small things is always praiseworthy.

The box contains:

The accessories are up to the class of the product, including a good software bundle besides the necessities. Here’s the graphics card:

Its PCB is red, which is typical of Palit, and non-standard. I’ll talk about it in the next section.

Pros and Cons of Non-Reference Design

What is the reference design of a graphics card, anyway? It is the PCB design that is optimal for mass production of the product and is developed by the GPU manufacturer. Any company that makes mass products tries to reduce the manufacturing cost, but also to ensure a stable and reliable operation of the product within the set limits. The reference design may indeed be perfect like with the PCBs for 6600 series graphics cards. Or it may not. For example, it was extremely hard and next to impossible to overclock the memory on the old entry-level ATI Radeon 9200 even to the nominal frequency of the chips, although the earlier ATI Radeon 9000, on a somewhat different PCB, was free from that problem.

If the graphics card manufacturer (not the GPU manufacturer) decides to change the PCB design, it doesn’t necessarily mean it will come up with something worse than the reference design. There are quite a lot of examples to the opposite, like about a quarter of all cards made by ASUS or Sapphire’s Ultimate and Toxic series.

I think that Palit Corporation has a very potent engineering team because a majority of products coming out under Palit’s trademarks differ from the reference design. So, they have to redesign everything, each model and each variety, before the product appears on the market ant meet the main goal, i.e. to reduce the manufacturing cost while keeping the product quality and functionality on the same level.

Redesigning a PCB boils down to the following:

I hope it’s clear that developing and using non-reference PCB designs for computer devices doesn’t mean “worsening” the original. It is rather a change or modification. In some cases the resulting product may even boast a higher quality of manufacture than the original.

Specification

Graphics core: Nvidia GeForce 7600 GT (G73-GT)

Default frequencies: 575/700(1400) MHz (GPU/memory)

Pixel pipelines: 12

Vertex pipelines: 5

Memory: 256MB GDDR3

Memory bus width: 128 bits

Memory chips: 1.2ns Samsung BJ-12, BGA

Interface: PCI Express 16x

Video interfaces: DVI-I, D-Sub, TV-out

RAMDAC: 2 x 400MHz

Closer Look

Now let’s take an inquisitive look at the graphics card’s PCB:

You can see that the special feature of this card is the redesigned power circuit. This is meant to reduce the cost of the product and shouldn’t be a problem if the main components get stable power and the regulator can provide a higher output current and voltage when necessary (for overclocking with and without volt-modding).

We’ll see the worth of this modified PCB design in practical tests below. Right now, let’s learn more about the card’s technical characteristics.

The N73-GT revision A chip on our sample of the card is dated April 2006. It has a clock rate of 575MHz, i.e. 15MHz above the core frequency of the reference card. There is a protective frame of some porous material around the chip. This is quite an important trifle.

It’s good for the end user whereas the manufacturer reestablishes its good reputation by paying attention to such small things. As you know, there is usually no such frame on GeForce 7 series cards. Here’s a non-reference design to you: Nvidia tried to cut the manufacturing cost, but Palit makes amends for the GPU maker’s weakness.

We’ve got another and bigger surprise as we approach the memory chips. The Palit graphics card carries Samsung’s chips with a fetch time of 1.2 nanoseconds (this means a frequency of 800 (1600) MHz) instead of 1.4 nanoseconds (a frequency of 1400MHz). The four chips give you a total of 256MB; there are seats for four more chips on the reverse side of the PCB. So, the manufacturer has left some room for further maneuvering: they can release a top version of the card with 512MB of memory or use lower-density chips to make the card cheaper.

It is with the 1.2ns chips that the Sonic card differs from Palit’s ordinary GeForce 7600 GT on the same PCB design. Using better chips, the manufacturer set their frequency at 750 (1500) MHz which is higher than the reference frequency of 700 (1400) MHz. This isn’t much of a growth in comparison with the EVGA e-GeForce 7600 GT CO Superclocked, for example, but good enough, anyway.

The way the cooler is fastened to the card is interesting, too. To remove the cooler, you only have to release the four hooks that hold on to the mounting plate on the reverse side of the PCB. The whole process takes less than five seconds, that’s how fast and easy it is. However, I am personally an opponent of such fastening systems and will not change my opinion in spite of all the advantages of that mechanism.

The problem is in the layer of a synthetic dielectric between the back-plate and the PCB:

So, the hottest part of the card’s reverse side finds itself in what is virtually a heat bag and the temperature of the 7600 GT can only but grow under such conditions. This is not much of a problem at the default frequencies, but an overclocker will have to change the cooler.

The cooler has a simple design: a blower in a plastic casing and a small aluminum heatsink. There’s thermal grease between the core and the cooler:

The cooler proved to be much less louder than I had expected. It is in fact one of the quietest among blowers of that type, so the Palit GeForce 7600 GT won’t break your acoustic comfort. You shouldn’t be worried about the small size of the cooler. It does its job well: the GPU temperature wasn’t higher than 65°C at the default frequencies during tests on an open testbed.

The sticker with the model and the serial number looks intriguing:

Is Palit going to release a 7600 GS with the same PCB design as the 7600 GT and with GDDR3 memory?

The card has a D-Sub instead of a second DVI output, which looks like a drawback to me. The remaining DVI-I has the dual-link functionality, though, and this graphics card can output to XHD monitors in resolutions up to 2560x1600.

I reached 628/832 (1664) MHz frequencies when I overclocked the card with its native cooling system on an open testbed. When I improved the thermal conditions by installing a liquid cooling system, I recorded a 15MHz core frequency growth under the same conditions. This is an average result for the 1.2ns memory chips. It turned out, however, that the memory was not to blame. Palit’s engineers just set 1.8V as the default memory voltage for this card instead of 2.0V voltage which is normal for the 7600 GT.

That’s the end of the descriptive part and we can move on to the point of the review – overclocking with volt-modding.

But first read our disclaimer and think again if you really need that.

Disclaimer

The modifications described in this article have been successfully made in practice. Each mod was tested by us and helped to achieve the desired result. We don’t accept any claims concerning damage to your graphics card or any other PC component after the modification – such problems imply your own mistakes. The author and X-bit Labs are not responsible for any damage inflicted by repeating anything of what is described in this article. We also cannot promise you that your final result will be as good as ours due to the variation in the potential of particular samples of graphics cards.

Warning! Volt-modding, if recognized, makes all warranty obligations void.

You should take up volt-modding if all the following items are true:

Before doing any volt-modding, make sure the graphics card is properly cooled (the standard cooler may turn to be insufficient even for ordinary overclocking).

Ingredients

So, you’ve made up your mind? Let’s move on then. In order to experiment with a Palit 7600 GT, you need:

The three last items can be replaced with an ordinary lead pencil, but we don’t use it often due to certain drawbacks. The lead from the pencil may crumble, so such a modification isn’t long-lasting. Moreover, you have to be very careful when “drawing” a resistance, and there’s a bigger risk of putting your graphics card to death than at ordinary volt modding. On the other hand, you can quickly remove all the modifications from your card.

So, it’s up to you to choose the particular tools. We are going to tell you how to use them.

We’ll be working upon the top right part of the PCB of the non-reference 7600 GT:

Core Volt-Modding

Find a resistor marked as R37 on the PCB:

Solder a 10,000Ohm variable resistor to this R37 or draw over it with a lead pencil. The original resistance is 1150Ohms. You can now reduce it in steps of 115-125Ohms to increase the core voltage in a step of 0.1V.

The core voltage is monitored on the legs of the top row of capacitors.

The default voltage on my sample of the card was 1.3V. I increased it to 1.55V and achieved a rather high core frequency of 745MHz.

Memory Volt-Modding

This modification isn’t any more complex than the core volt-mod. You should solder a 10,000Ohm variable resistor to the resistor marked in the picture (R34):

Or draw over that resistor with a lead pencil.

The voltage is monitored on the legs of this capacitor:

Warning! If you are guided by the recommendations fromvr-zone.com, make sure you’re using their monitoring points – they are different from ours!

On my card, the original memory voltage was 1.81V. I increased it to 2.0V (by reducing the R34 resistance from 625Ohms to 540Ohms; in other words, a 0.1V voltage increase is achieved by reducing the mentioned resistance by about 40Ohms) and reached a memory frequency of 855MHz. This is comparable to the best results of other versions of the GeForce 7600 GT where the memory voltage is initially set at 2.0V.

I also think that the memory chip on Palit GeForce 7600 GT Sonic cards can be overclocked to even higher frequencies. I increased the voltage to the value the chips are rated to work at, but it would be quite safe to lift it up to 2.2V (I just had too little time to modify and test the graphics card).

This is what the modified section of the card looks like:

Important Note

If you are going to overclock a Palit GeForce 7600 GT Sonic or its analogs in earnest, you have to take care about proper cooling of the graphics processor, memory as well as power elements installed on the card. When I was checking out the results of the modifications I accidentally touched the card’s edge and nearly scorched my fingers! (It was before I installed a fan to blow at the reverse side of the PCB). So, if you are into serious overclocking, you must install heatsinks on the MOSFETs shown in the picture and, if possible, provide some air cooling for that section of the card.

Otherwise the components may overheat and fail. The high temperature of the PCB may have a negative effect on the overclockability of the memory chips, too.

Testbed and Methods

The graphics card was benchmarked on an open testbed that consisted of the following components:

The CPU worked at a frequency of 2800MHz (350x8) with 1.55V voltage. The memory worked as DDR-133; its resulting frequency was 233MHz with 2-2-2-5-1T timings and 3.25V voltage.

The testbed ran Windows XP SP1. The card was overclocked with PowerStrip 3.62; the frequencies and temperature were monitored with RivaTuner 2.0 RC16. The GPU was cooled by the water-block. A 120mm fan was additionally installed to blow at the reverse side of the PCB:

Performance

I didn’t run a full cycle of tests since we recently benchmarked a GeForce 7600 GT. The Palit card behaves exactly like the EVGA e-GeForce 7600 GT at the same frequencies (for details see this article). So, there is only one benchmark today, 3DMark03 Pro 3.6.0. Its results will show you the effect from overclocking the reviewed graphics card with and without volt-modding.

The benchmark’s settings were left default. The graphics driver settings were selected as to provide an optimal quality/performance ratio.

The performance is high, just like the overclocking gain. By the way, I didn’t squeeze the maximum out of my sample of the card. There was still a considerable safety margin. Besides, it is possible to climb up to an even higher performance level by increasing the frequency of two out of the GPU’s three main subunits (you can select a negative delta for the geometry subunit by modifying the graphics card’s BIOS). I didn’t plan to do that for this review and didn’t check this possibility out in practice.

Conclusion

So, my verdict on the Palit GeForce 7600 GT Sonic is that you shouldn’t shun this graphics card notwithstanding its non-reference design. On the contrary, I do recommend that you consider it when you go shopping.

Highs:

Lows:

I strongly recommend to volt-mod the Palit/Gainward GeForce 7600 GT on this PCB not only to get the maximum out of the graphics card in extreme modes, but just to increase the overall performance of the graphics subsystem (considering the initially lowered memory voltage). Moreover, this volt-mod is simple and reliable. Just do not forget about the safety measures mentioned above!

Good overclocking luck to you!