AMD 7990 - Reference Design? Overclocking?

[Quantumn]

Just bought two 7990's, a Gigabyte and a Diamond. I'm reading that some brands are reference design, and some aren't.

I know that the 7990 comes in these brands: XFX, Powercolor, MSI, Gigabyte, Diamond, Asus, and maybe a couple more. So which of these are the reference design? I've searched all over ixquick and can't find this info.

Also, I believe this card can be overclocked, but only so far. I will be water cooling with EK full jackets, so am not worried about the heat. What's the best I can overclock these. I'll be mining.

I read that voltage may be locked. True? Is it possible to cut a trace or something and unlock voltage? Or is Asus the only one with Vcc unlocked?

And I read that improved firmware can be flashed. Can someone please advise on this?

I read that with multiple cards in the system, that those without a monitor will not work. Is there a way I can hotwire a plug to make it think there's a monitor?

 

[SolMiester]

I have no idea about clocking 7990, though I dont believe its flash!. What screen\s are you using with them...

 

[Enigmoid]

I recommend reading the toms hardware review of the 7990 in crossfire. I believe they had massive temperature problems.

http://www.tomshardware.com/reviews/radeon-hd-7990-crossfire-overheat,3539-2.html

 

[biostud]

if it looks like this:

It's the 375W TDP version made by AMD

If it looks like this (or similar cooler):

it's the pre-AMD 7990 with 500W TDP.

You can overclock them 1100Mhz in the CCC. My 7990 has a voltage slider in the CCC that goes from -20% to +20%.

 

[3DVagabond]

Just bought two 7990's, a Gigabyte and a Diamond. I'm reading that some brands are reference design, and some aren't.

I know that the 7990 comes in these brands: XFX, Powercolor, MSI, Gigabyte, Diamond, Asus, and maybe a couple more. So which of these are the reference design? I've searched all over ixquick and can't find this info.

Also, I believe this card can be overclocked, but only so far. I will be water cooling with EK full jackets, so am not worried about the heat. What's the best I can overclock these. I'll be mining.

I read that voltage may be locked. True? Is it possible to cut a trace or something and unlock voltage? Or is Asus the only one with Vcc unlocked?

And I read that improved firmware can be flashed. Can someone please advise on this?

I read that with multiple cards in the system, that those without a monitor will not work. Is there a way I can hotwire a plug to make it think there's a monitor?

With full cover blocks you should be good to go. I wouldn't want to run a card like that purely on air. I'm not sure which are voltage locked or not. If it's the reference model (2 slot) you should be able to get an unlocked bios if yours is locked.

 

[Quantumn]

if it looks like this:
It's the 375W TDP version made by AMD

This ^.

You can overclock them 1100Mhz in the CCC. My 7990 has a voltage slider in the CCC that goes from -20% to +20%.

What's a CCC? Chaos Computer Club? (I'm a Linux type) Sounds pretty easy with the right app. What brand of 7990 do you have?

I'm starting to gather that all with the red fans are supposed to be the reference design. But there has to be some difference, as the XFX's and PowerColoreds have had alot of problems.

3DVagabond, thanks. Y, I'll be using these and this on this with this. A kickass Gen 3 PCIe server mobo with a very energy-efficient CPU. I don't need alot of CPU for mining, but DMA is paramount for scrypt. Anyway, I should be able to OC the CPU with water-cooling, if I need it. That damned low-W server CPU was really hard to find, but one place in NorCal had it. This machine also does my home theater, and really should be as quiet as possible.

I'll search around and try to find out more about the bios. I believe this card has switchable bios, so if a flash fails you're not dead. Nice, but expected feature in a card this expensive. Unlocking that voltage will be key to getting extraordinary clock, if it's possible. I'll be using an adapted car heater for the heat exchanger, lol.

On whether a dummy plug is needed, it seems that AMD found it is a PITA, so they've removed the monitor requirement in drivers now.

 

[biostud]

CCC is catalyst control center, which comes with the amd drivers for videocards. Although I'm not an expert on mining, the performance/watt decrease drastically when you overclock the GPU. I have an XFX.