7900 vs 200 vs 300

[nrobidoux]

Was curious on people's opinions. I've been looking at 7900s for years and years and finally decided to dive in... Jan 2014.

Did some searching yesterday as I'm trying to sell some components on eBay and at some point the 300-series came out. Sure as time progressed they put in a few more compute units, increased memory bandwidth a little, increased clock speeds a little....

I can see the 7900 series on the way out the door but I don't really feel it's obsolete. Guess I'm looking for people's experiences that have tried the different cards. I know there's some improvements but is it worth getting a new card yet? I know several cards are comparable and some are seemingly just rebranded. The only real obvious difference I see is 8GB vs 3GB of GDDR5.

 

[ultima_trev]

Um, the R9 390X is is a massive upgrade to HD 79xx series. You'd see at least a 50% gain on average, nevermind the much better tessellation performance and support for DX12 (79xx only supports 11.3).

 

[thesmokingman]

It's a good to great upgrade, but not massive.

 

[Headfoot]

Um, the R9 390X is is a massive upgrade to HD 79xx series. You'd see at least a 50% gain on average, nevermind the much better tessellation performance and support for DX12 (79xx only supports 11.3).

79xx supports DX12.

 

[Mercennarius]

79xx supports DX12.

Correct. Core DX12 features supported but not all DX12.

 

[nrobidoux]

Like your sig Headfoot. I was thinking along the same lines.... namely if I swapped all the 65Ws in the common areas (14) which we left on a lot. When I fold with 7 7950s my employer wouldn't notice much of a change.

Back on topic, seems like a lot of little improvements add to a big one.... but seems not so big a change from the 290 to 390. Yes?

I guess where I'm going with this is that is there any major improvement you can see gaming? What games are you playing?

Right now I'm on an Elite Dangerous kick and I maxed out the settings with one 7950. Unfortunately that system is shelved for a bit until I do some cleaning and install this...

 

[Techhog]

Like your sig Headfoot. I was thinking along the same lines.... namely if I swapped all the 65Ws in the common areas (14) which we left on a lot. When I fold with 7 7950s my employer wouldn't notice much of a change.

Back on topic, seems like a lot of little improvements add to a big one.... but seems not so big a change from the 290 to 390. Yes?

I guess where I'm going with this is that is there any major improvement you can see gaming? What games are you playing?

Right now I'm on an Elite Dangerous kick and I maxed out the settings with one 7950. Unfortunately that system is shelved for a bit until I do some cleaning and install this...

... I have several questions.

 

[Shmee]

wow

 

[Makaveli]

 

[thesmokingman]

Mining array with crossfire bridges for quadfire for gaming. But damn that must be some serious restriction.

 

[nrobidoux]

What are the questions? I need a few more posts/days before I can sell.

If you're curious... let me rephrase... My configuration has never been put into a computer and turned on yet. I did mine for scrypt coins. I had two circuits, one on board, one on risers. Something like:

Circuit: 2 D5 pumps -> GPUS -> MORA 420

The circuits were:

• 2 HIS 7950 IceQ w/ Boost
• HIS 7950 IceQ -> 2 HIS 7970 IceQ X2

I wanted to take my computer out of a milkcrate and give it a proper case. That resulted in a choice: custom aluminum angle iron or just buying one. I bought one, which meant needing to find components to make it work.... think I have... we'll see after I sell some things and clean to make room for this thing. (Just moved.)

This thing has been a process.

Mining array with crossfire bridges for quadfire for gaming. But damn that must be some serious restriction.

Kinda. Dropped mining for folding.

We'll see what happens. Will be 3 D5 pumps -> 7 HIS 7950 IceQ w/ Boost -> 2 MORA 420s

 

[Headfoot]

290 -> 390 was a refresh. Same core chip, they jiggered with some low level stuff so that it clocks a bit higher but uses no more power to do so. It has faster memory and more of it, and thats pretty much it.

 

[thesmokingman]

290 -> 390 was a refresh. Same core chip, they jiggered with some low level stuff so that it clocks a bit higher but uses no more power to do so. It has faster memory and more of it, and thats pretty much it.

Actually, the 390 seems to use a bit more power and it doesn't seem to clock higher on avg.

 

[Techhog]

What are the questions? I need a few more posts/days before I can sell.

If you're curious... let me rephrase... My configuration has never been put into a computer and turned on yet. I did mine for scrypt coins. I had two circuits, one on board, one on risers. Something like:

Circuit: 2 D5 pumps -> GPUS -> MORA 420

The circuits were:

• 2 HIS 7950 IceQ w/ Boost
• HIS 7950 IceQ -> 2 HIS 7970 IceQ X2

I wanted to take my computer out of a milkcrate and give it a proper case. That resulted in a choice: custom aluminum angle iron or just buying one. I bought one, which meant needing to find components to make it work.... think I have... we'll see after I sell some things and clean to make room for this thing. (Just moved.)

This thing has been a process.



Kinda. Dropped mining for folding.

We'll see what happens. Will be 3 D5 pumps -> 7 HIS 7950 IceQ w/ Boost -> 2 MORA 420s

I hope 3 pumps is enough. I honestly can't even think of a sufficient number of radiators.

Anyway, that answers the what and the why (sorta), so all that's left is... how?

 

[aaksheytalwar]

Going from a 7970ghz to a 290X should yield a gain of 40-70%. A 390% will be faster still.

 

[biostud]

390X has 20% faster memory than 290X and double the amount.

 

[VirtualLarry]

Um, the R9 390X is is a massive upgrade to HD 79xx series. You'd see at least a 50% gain on average, nevermind the much better tessellation performance and support for DX12 (79xx only supports 11.3).

Not for DP. (MW@H on BOINC)

 

[nrobidoux]

I hope 3 pumps is enough. I honestly can't even think of a sufficient number of radiators.

Anyway, that answers the what and the why (sorta), so all that's left is... how?

Not quite sure as to what you mean. I decided to plumb these in parallel... and from another thread where I asked the question... peeps think series will be better. The only problem with series... well there's two.... the one I was thinking of was I have 7 cards that can pivot around when trying to insert this block into the mobo. Fiddling with two or three was a pain. I can't imagine 7.

The other is the temp gradient. This is countered by more flow.

The advantage to parallel is that the resistance is either divided by the number of cards, like an electronic circuit or is just the same as an individual unit. Flow rate suffers of course because, let's assume the cross-sectional area remains the same in the waterblock, there's a 7-fold increase from the inlet tube to the GPUs. But temps should be more uniform.

If I went series.... aside from what I mentioned above, the resistance is summed. IDK why I thought that was a big deal until literally typing this post.

Why? Because it is not uncommon to have 2 GPUs in Crossfire / SLI with one pump. Flow doesn't change in series, just resistance. In my circuit there's 2.33333 cards per pump... not that much of a change over 2.

Unfortunately a rod doesn't work to keep the cards in line.... unless I don't intend on removing it from the case once the cards are installed. Was thinking I'm going to have to get six balls and place them in alternating connectors between the cards.

As far as connectors went, found the smallest I possibly could (11-18mm adjustable) and then found a machine shop to bring them down to 9mm.

As for radiators 120x2 is typically recommended per GPU. I have 140x18. My fans run pretty slow though (700 rpm). It is the quietest, most expensive, and most effective space heater I've ever seen.

 

[nrobidoux]

Going from a 7970ghz to a 290X should yield a gain of 40-70%. A 390% will be faster still.

I'm assuming this wide range of gain is the result of overclocking? Multiple sites indicate a 50% improvement from a stock 7950 to a stock 290X/390X. I would think the improvement from a 7970 would be less.

Either case, I thank the peeps for contributing to the thread. Seems pretty clear there's a definite improvement from the 7900-series.

 

[RussianSensation]

I'm assuming this wide range of gain is the result of overclocking? Multiple sites indicate a 50% improvement from a stock 7950 to a stock 290X/390X. I would think the improvement from a 7970 would be less.

Either case, I thank the peeps for contributing to the thread. Seems pretty clear there's a definite improvement from the 7900-series.

Since you have so many 7950 cards, it's enough to sell them and get a GTX980Ti.

If you aren't gaming at 1440P, $280 GTX970/R9 390 are great values but if you are considering buying 2 of each, just get a single 980Ti.

http://forums.anandtech.com/showthread.php?t=2454100

What CPU do you have? I didn't see you mentioning that.