*** Official AMD 7990 Owners Thread ***

[Catanonia]

What about 2 7990's in games would I see a benefit as I already got one but it's hard to pass up another at that price.

Not really tested it myself.

The two I have under water are awesome on benchmarks, and well I play Crysis on full settings @ 1440 mode no problems at all. Overkill definitely, but nice to have the power.

The reason I got a second was the price and that I Mine LiteCoins earning me about $18 a day at the current Litecoin prices

 

[Catanonia]

Lite coin, I wish it was bit coin at the prices. Lite coins slowly rising so one can dream.

Well Litecoins now @ $21 per coin and my 2x7990 are generating 2.1 Litecoins a day as we speak. This is a combined has of 3500 kHashes per second.

Yes that is $42 - $45 a day depending on network speed and price.

They are water cooled and left running 24/7 whilst at work. Only get switched off for a few gaming sessions.


At this rate they will have paid for themselves soon.

 

[Catanonia]

I got a game card with mine that had 8 games - the XFX 7990. Sold a couple to my mate for £20, I might stick other keys on here for couple of quid (or just keep em).

I should hopefully get the PSU too that I persisted over so overall not bad for £399.

pretty sure the game codes are now expired ?

 

[Catanonia]

I did indeed Matt but change is allways good. Had saved me pennies towards these classified 780ti's whenever they land but the opportunity to be able to claw back costs seemed an opportunity I could not pass up

More like the draw of LiteCoins wasx just too much

 

[Catanonia]

Yeah I seen one guy here mention he makes £3 a day profit overall. Not worth the effort if that's the case.

ages ago when the price was low.

I am making about £40 on 2x7990 and that is after removing leccy costs based on current prices

 

[Catanonia]

Is that 24/7 mining?

Of course, sometimes it is switched off for a few hours gaming.

 

[Catanonia]

I could probably only do 8 hours a day or so. I couldn't sleep with it mining

Mine is in the office at home, so no problems

 

[Catanonia]

lol @ speirs

You sir need to try the "blue" pills Can't see anything wrong Maybe the res.

 

[Catanonia]

LOL I remember I was one of the very 1st to get the Sapphire 7990 from OC when they were released, a snip at £845

Might sell it and recoup after the ltc craze has finished to some noob

 

[Catanonia]

Sorted it: I switched to GPU 2 in AB, then back to GPU1 and the voltage was at 1.2v.
I then had to apply 1.135v about 4 times for it to work.
Bizarre.

I suppose I should check if the voltage sticks after a restart.

This happened in the older AB versions a lot. Check you have the latest. Since the latest my sticking issues have disappeared.

 

[Catanonia]

Why does my Afterburner keep telling me that it is going to expire?

/facepalm Have you actually read it !!!!! ?

Try reading the error message the answer is there.

Or in case you are too lazy to, the beta is going to expire next weekend, you need to get the newer one.


Jeez, I hated people like you as a programmer. I would put every effort into a program with clear instructions it would fail at the 1st obstacle, the human and oh, never mind

 

[Catanonia]

For those with temp problems / differences between the cores I went through the same problem many months in this thread.

My problem was also highlighted through mining and turned out to be a combination of flex and thermal paste. The extremes of mining highlighted the problem with core differences starting at 3 degrees and going to 15+ over a period of a day.


Flex : the card is heavy and it pulls the heatsink off one of the GPU's by a small amount, enough to give problems.

Paste : Many times of messing with paste and sorted this out, make sure enough is applied.

I solved the flex problem by propping up the card with a piece of wood.

Also I noticed that as I was under water, the direction of my loop was critical to stopair bubbles. This may also have been a contributing factor.

 

[Catanonia]

This might take a fair bit of testing, but I just took it apart and put different paste in. (Akasa stuff that came with my Alpenphonn Mount Doom Heatsink I believe) As previously I put a small amount of Arctic Silver 5 in. I went for the less is more approach of cpu's as it's rather conductive to electricity, so didn't want spillages.

Having been re-inspired to have a go at self remedy I decided to put more of this paste on than the arctic silver.

After a run on 3dmark (where I got 101c on gpu 1), I didn't go over 91c this time, however gpu2, which I don't see go over 72c actually hit 76c at one point. I will just keep testing etc over the next few days to a week and see if the paste sets in and improves. Still the results seem a little baffling and may take a bit more testing to see where my temps consistently lie.

One thing I did notice was gpu1 temps are dropping quicker when the it's no longer under heavy load, more akin to that of GPU2. The gap is still a bit big, but if I can start getting a grasp on whether gpu1 is controllable, then I will muster up the courage to build my first water cooling system for it.

Between the general fear of my first attempt at water cooling and fear that I may be throwing hundreds of pounds to cool a card that may be faulty. It's something I have serious reservations about. So I will work to get the card to be more manageable and if I achieve that, then I will throw it under water and see where that gets me. Dammit, 7990's been selling like hot cakes, some smart cookie should bring out an aftermarket air cooler for this bahemouth! (Not going to happen I know )

Just double check with GPU-ID that you are putting the same voltage across both GPU's. Early versions of AB and Trixx didn't do this correctly even when sync'd and sometimes took several applies on the set button to make them even.

 

[Catanonia]

Just double check with GPU-ID that you are putting the same voltage across both GPU's. Early versions of AB and Trixx didn't do this correctly even when sync'd and sometimes took several applies on the set button to make them even.

 

[Catanonia]

I am going to give this a few tests, but it appears, propping the card up is a step in the right direction so far. It's not ground breaking and the gap is still big, but it may well be improving my temps.

Let everything cool down and start the tests.

These cards definitely suffer sag, even with the back plate on. This thread has some of my posts on it back in the early posts.

I fought uneven temps on the GPU's for ages and found that in order the following were the culprits.

1. Uneven voltage settings in AB and Trixx
2. Card Sag
3. Thermal Paste

All of these contributed to the problem.

The temps on my 2 x 7990 are never more than 3 degrees per card which is acceptable under water considering one is cooled after the other per GPU.
Of course my 2nd card in the loop is higher, about 10% as it has water heat from 1st card in CX .

 

[Catanonia]

Fell asleep watching extra time of Sunderland vs Chelsea snip.

I put enough piece of wood underneath to prop up the card just enough to take the pressure + a bit, do not force the card up too much, just take the weight + a nads butt so slight upward pressure.

 

[Catanonia]

All of you having temp problems,

Simply lifting cards with zip ties might not work depending on how you attached them.

Propping up from bottom with a wooden block to take the pressure + a little bit will ensure the heat sinks are pushed against the GPU dies instead of supporting the card.

The flex I am talking about is the smallest amount of heat sink to GPU die gaps that happen as the card warms up and the board separates from the heat sinks at the die level by the smallest amounts giving one gpu higher temps.

That is the way to do it.

 

[Catanonia]

Same here, been considering profiteering on my 2x7990 + blocks, but what would I replace them with ?