Overclocked Video Cards?

[Gigabite]

Hi

I have a Sparkle geforce 8600GT and i overclocked it from 540MHZ (core clock)/1190MHZ(shader clock) to 620MHZ/1270MHZ. I see that many manufacturers are selling overclocked models of the 8600GT. I was wondering why do they overclock it, when you can permanently change the frequencys by yourself using Nibitor and Nvflash? Do they redesign the GPU chip so that its MHz can be raised?

Thanks

[Rick]

In many cases it is Just a matter of cooling
Look at the heavy over clocked models

The Heat shrinks and fans are way over grown

If you have over clocked your stock model.
Keep and eye on the temperature
If it starts to go up.
Then get a better cooler and or fan

If it cooks and your return it for warranty work.
You are out of luck with an over clocked and cooked chip

[TopChip7]

Ricks right - pre-overclocked cards are covered by warranty - overclock yourself and void your warranty.

I got 2x 7900GT SLI 450mhz/1320mhz stock running at 570mhz/1550mhz and I believe I could push them quite a bit further if I wanted to. However, I would NOT have changed the clock settings without spending hard cash on VGA coolers.

The whole point is if I was to buy the GTX's I'd have paid an extra £100GBP on each card - however, the Zalman VF900-CU Led Fans only cost me approximately £20 each. Great savings but obviously results will vary and some cards will not overclock at all.... perhaps I was lucky!!!

From reviews I've read it seems that overclocking the VGA depends upon the quality of the memory on the card. Pre-overclocked cards are made with good quality memory tested to run at the speed they're sold at. However, stock speed cards can come with quality memory that will overclock more than adequately.... but you are taking the risk and every memory module will vary.

[Gigabite]

Memory of the card is the most important? I would of thought the core chip would be the most important. What do you mean by quality memory? I have hynix memory on my 8600gt, is that any good? It runs very stable at 620mhz/1270mhz, and ive even got it up to 720mhz/1420mhz, running stable and cool. But i went back down to 620mhz/1270mhz just to be safe :)

What are the top best brands of memory?

[TopChip7]

Some modules simply operate better than others. It could be down to several reasons however the easiest way to explain it is that one may have a better solder than another.

The design of the memory a company make is say 1500mhz and apart from faulty modules all of it will operate at 1500mhz. However, perhaps 15% of the modules simply operate better than their design and may run at a maximum of say 1800mhz. The manufacturer checks each module to ensure it passes its 1500mhz. The better modules that pass at higher mhz are sometimes put to one side to create overclocked versions of the card.

Now I may be wrong but if a large batch of modules comes off at superb speeds and its not all required for infrequent selling o/c vga's then it all goes through and put on normal spec cards - hence being able to o/c your card.

Possibly not the best way to explain it but I hope it helps