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anticitizenzero
12-12-05, 01:47 AM
Ok, i'm not an expert on video cards so they may kinda sound like a n00b question. If I were to put say a 512 7800's cooler on a 7800 GT or GTX how come I can't overclock it to those same speeds if it has the upgraded cooling, what exactly is causing artifacts other than heat??

AthlonXP1800
12-12-05, 01:57 AM
The reason 7800 512 has higher clocks because the core is based on new revision A2 2005 Week 39, the GTX 256 is based on older revision A2 2005 Week 17.

phide
12-12-05, 01:57 AM
G70 Ultra/G70U (GTX 512) is a revised chip, not just a G70 (GTX 256).

G71 (7900?) may not clock as high as R580 (X1900 XT) simply because they're differently designed chips even though the manufacturing process (90nm) is the same.

Get all that?

technoid
12-12-05, 07:02 AM
From what I understand nvidia didn't modify the gtx chip to get higher clocks they worked with tsmc to tweak the fab process to produce better quality dies. The thing with chip making is they're "all" different, each batch of chips is slightly different than the others so each batch will run at varying clock speeds. So when you get the fab process working it's best you get the highest quality chips and they will run faster. Then after they're cut and tested you "bin" them, which means test each chip to see how fast it will run. That's how nvidia was suppose to have gotten the chips for the 512, by tweaking the fab process for higher quality and binning the chips as they come off the line.

Scott@Bjorn3D
12-12-05, 07:32 AM
My understanding is NVIDIA has done speed binning for a long time. It started back with TNT's but really started being used more with the TI 4 series and the 6800 series. Speed binning is the way to go in my mind, aim for high speed chip and those that do not make it become lower end models.

I do not think that even NVIDIA was ready though for the demand of GTX 512MB's, but I am sure they felt they had to answer the X1800XT.

a_big_burger
12-12-05, 09:31 AM
From what I understand nvidia didn't modify the gtx chip to get higher clocks they worked with tsmc to tweak the fab process to produce better quality dies. The thing with chip making is they're "all" different, each batch of chips is slightly different than the others so each batch will run at varying clock speeds. So when you get the fab process working it's best you get the highest quality chips and they will run faster. Then after they're cut and tested you "bin" them, which means test each chip to see how fast it will run. That's how nvidia was suppose to have gotten the chips for the 512, by tweaking the fab process for higher quality and binning the chips as they come off the line.
Agree! There is an article supports the above explaination! Someone posted link somewhere in the forum. It is the same chip. Only differences are
1) Nvidia asked TSM to tweak the fab process to produce better quality and
pick the best chips for the 512 7800GTX
2) Changed the PCB board to add more voltage on the chip
3) Use large heatsink to cool it down. My 512 runs very hot even with the
stock cooler.
4) The highest overclockable 7800GTX 256 is the LeadTek 7800GTX extreme.
532/1380 can be done. It is selling on EBay:
http://cgi.ebay.com/Leadtek-WinFast-7800-GTX-Extreme-PCI-Express-256MB_W0QQitemZ8735575103QQcategoryZ40161QQrdZ1QQc mdZViewItem

Riptide
12-12-05, 10:22 AM
So how much of a rape do you guys think I could get for my GTX512 on ebay? :p

$1000? $1200?

technoid
12-12-05, 10:44 AM
My understanding is NVIDIA has done speed binning for a long time. It started back with TNT's but really started being used more with the TI 4 series and the 6800 series. Speed binning is the way to go in my mind, aim for high speed chip and those that do not make it become lower end models.

I do not think that even NVIDIA was ready though for the demand of GTX 512MB's, but I am sure they felt they had to answer the X1800XT.
Correct, they've been speed binning for a long time. It's the normal way to deal with getting faster and slower chips to the market, most companies do it. But a lot of people don't understand how the chip business works and thinks there's actually different chips made for different products. Of course at times that's true but when two graphics chips are being sold that are identical except for the speed at which they operate then speed binning is the way they do it. CPUs are done the same way.

technoid
12-12-05, 11:02 AM
Agree! There is an article supports the above explaination! Someone posted link somewhere in the forum. It is the same chip. Only differences are
1) Nvidia asked TSM to tweak the fab process to produce better quality and
pick the best chips for the 512 7800GTX
2) Changed the PCB board to add more voltage on the chip
3) Use large heatsink to cool it down. My 512 runs very hot even with the
stock cooler.
4) The highest overclockable 7800GTX 256 is the LeadTek 7800GTX extreme.
532/1380 can be done. It is selling on EBay:
http://cgi.ebay.com/Leadtek-WinFast-7800-GTX-Extreme-PCI-Express-256MB_W0QQitemZ8735575103QQcategoryZ40161QQrdZ1QQc mdZViewItem
I've seen that article. I've also seen pictures that show the chip after the heatsink was removed for a 256 and 512 and they were both A2 Silicon.

The 512 is just a cool board, it walks softly and carries a big stick. That's why I want one :) But it's so hard to speed the big bucks on it now since I know a faster one is coming.

Does your core run as cool as the articles say? And is the cooler as quiet? What I think you're saying is the heatsink puts out a ton of heat and the board runs hot, but I assume the core temp is what I've seen in the articles.

a_big_burger
12-12-05, 08:31 PM
I've seen that article. I've also seen pictures that show the chip after the heatsink was removed for a 256 and 512 and they were both A2 Silicon.

The 512 is just a cool board, it walks softly and carries a big stick. That's why I want one :) But it's so hard to speed the big bucks on it now since I know a faster one is coming.

Does your core run as cool as the articles say? And is the cooler as quiet? What I think you're saying is the heatsink puts out a ton of heat and the board runs hot, but I assume the core temp is what I've seen in the articles.
I don't remember what reviews say about the temp. My BFG 512's temp is around 75 C when I play Quake4. (overclocked @ 590/1800) That is hot! Based on my experience, the chip won't be very stable if the temp is above 80 C. I don't think it is possible to play at > 600 Mhz core. You may play for 5 minutes and when it is getting hot, you will see artifact. The cooler is quiet. BTW

technoid
12-13-05, 10:50 AM
I don't remember what reviews say about the temp. My BFG 512's temp is around 75 C when I play Quake4. (overclocked @ 590/1800) That is hot! Based on my experience, the chip won't be very stable if the temp is above 80 C. I don't think it is possible to play at > 600 Mhz core. You may play for 5 minutes and when it is getting hot, you will see artifact. The cooler is quiet. BTW
Thanks for the information. I always prefer to hear from someone that actually has the board rather than a review. Here's what the review on Beyond3D had on the core temps.

Core Temperature (Degrees) 7800 GTX 512MB 7800 GTX 256MB 6800 Ultra 256MB
Idle 42 50 60
Use 71 74 70
Increase 29 24 10

So it looks like your's is right in line with what they said. It's sure great to hear the fan is quiet too. I always want my system to be as quiet as possible.

Thanks again for the information.