Can I run 3 x 7950 cards on 850w

LtMatt · 4 Apr 2013 at 09:53

tommybhoy said:
Andy's on a colossal biblical crusade against AMD at the moment, pedantically posting in almost every other thread, the hate is that bad he's even stooping as low as fabricating thread titles.

Andy is part of the Nvidia PR machine hard at work but as was shown in the Tomb Raider results on the other thread, don't believe all the Guff, only some of it is true the majority isn't.

andybird123 · 4 Apr 2013 at 10:07

if it's all guff then why have AMD posted up saying that they are aware of the issue and are going to release a patch in the next 3-4 months?

if I see independent testing that says that particular card setups have issues, and someone is asking about that setup, then I'm going to post the info I have, sorry if that offends you

you are right tommy, I don't have crossfire, by all means post up your personal experience... people will cherry pick the info they want to hear and make their choice anyway

just to be a little pedantic, but if you are using 120hz AND 3D then you are actually using 60hz effective...

I thought my thread title was hi-larious... not really my fault that you 2 had a major sense of humour failure over it

LtMatt · 4 Apr 2013 at 10:22

andybird123 said:
if it's all guff then why have AMD posted up saying that they are aware of the issue and are going to release a patch in the next 3-4 months?

Its an issue which affects some titles. However if you think the games listed (bf3, sleeping dogs etc) you linked are unplayable or not smooth in xfire then you're very much mistaken. I will trust the people that have xfire setups that i know and who tell me that things are fine rather than some review site that has been handed a tool created by Nvidia to measure frame times. Now its not to say that AMD can't make things smoother, they have said as much by doing what Nvidia do and deliberately add latency to smooth things out.

andybird123 said:
I thought my thread title was hi-larious... not really my fault that you 2 had a major sense of humour failure over it

I think you need to read that thread again Andy if you think it was just me and Tommy that had an issue with it. We know you like to troll though.

tommybhoy · 4 Apr 2013 at 10:43

andybird123 said:
if it's all guff then why have AMD posted up saying that they are aware of the issue and are going to release a patch in the next 3-4 months?

Aware of the issue and dramatising how unplayable using an AMD gpu is, are two different entitys.

Multi-GPU stuttering has become an important issue for AMD just as single-GPU stuttering has, and AMD is working on a resolution for it. That resolution will come in or around a July driver drop, at which point AMD will introduce some new driver options to control how their cards deal with the issue.

http://www.anandtech.com/show/6857/amd-stuttering-issues-driver-roadmap-fraps

New driver features are hardly simple patching.

Kudos to AMD for stepping up and publicly talk about their problems rather than shut down their forums and hiding from the stutter bug.

andybird123 said:
if I see independent testing that says that particular card setups have issues, and someone is asking about that setup, then I'm going to post the info I have, sorry if that offends you

you are right tommy, I don't have crossfire, by all means post up your personal experience... people will cherry pick the info they want to hear and make their choice anyway

Like asking about 3x gpu's for bitcoin mining=income, and that requires frametime comparisons for???

AMD tell their story, your portraying AMD driver performance as 100% broken, which it isn't as simple as you like to make out.

All you keep doing is dropping frametime comparisons-usually the worst offenders you can find, as well as failing to mention Nvidia have the same problem of runt frames-but not to the extent of AMD.

andybird123 said:
just to be a little pedantic, but if you are using 120hz AND 3D then you are actually using 60hz effective...

andybird123 said:
I thought my thread title was hi-larious... not really my fault that you 2 had a major sense of humour failure over it

LtMatt said:
I think you need to read that thread again Andy if you think it was just me and Tommy that had an issue with it. We know you like to troll though.

^
This, it was nothing to do with humour, it was all about slant.

OLDPHART · 4 Apr 2013 at 11:08

Tonester0011 said:
@stock the 7950s are pretty low power, trifire with a normal CPU loads at around 600W. With a gonna assume, overclocked hexcore and mild oc on the cards? you'll be pushing 800-850w. Still well within spec of an 850w Corsair unit.

+1, but don't forget the closer you run your PSU to 100% load depending on the make, you could have issue's. So for me l would pay that bit extra and have some reserve, when you plan your PC build l would rather put in a good 850W to cover up to x2 GPU'S / x3 1000W knowing you should not have any problem's.

Radeon HD 7950 - On your average system the card requires you to have a 500~550 Watt power supply unit.
Radeon HD 7950 Crossfire x2 - On your average system the cards require you to have a 700 Watt power supply unit as minimum.
Radeon HD 7950 Crossfire x3 - On your average system the cards require you to have a 850~900 Watt power supply unit as minimum.

Locky · 4 Apr 2013 at 11:10

Games for me run smooth, BF3 for me runs like butter.

andybird123 · 4 Apr 2013 at 11:10

tommybhoy said:
Like asking about 3x gpu's for bitcoin mining=income, and that requires frametime comparisons for???

it didn't, I already admitted that, I would have said nothing else in this thread if you and matt hadn't been jumping up and down to also chip in with your irrelevancies

tommybhoy · 4 Apr 2013 at 11:24

It's all relevant from more than two AMD users pouring doubt on poor biased posting.

Sin_Chase · 4 Apr 2013 at 11:25

Kotu said:
£70 a week (using 3 7950 without taking into account electricity cost) is a waste of time? At the current prices its well worth doing for a bit of extra pocket change

I highly doubt that, mining is one thing.....competing in the market to sell them is another. ASIC will come along and 10s of other factors will affect profitability.

andybird123 · 4 Apr 2013 at 11:26

tommybhoy said:
It's all relevant from more than two AMD users pouring doubt on poor biased posting.

one of whom doesn't even have crossfire, very relevant

Rusty0611 · 4 Apr 2013 at 11:43

andybird123 said:
one of whom doesn't even have crossfire, very relevant

Not worth it - just ends up with pages and pages of twisting and turning

.

andybird123 · 4 Apr 2013 at 11:46

Rusty0611 said:
Not worth it - just ends up with pages and pages of twisting and turning .

I know, I'm done in this thread, I already admitted that crossfire gaming results make no difference to bitcoin mining :rolleyes:

tommybhoy · 4 Apr 2013 at 11:47

Matt used CrossFire for long enough-he's very aware to the positive/negative workings of CrossFire hence his welcome advice in his helpful threads.

LtMatt · 4 Apr 2013 at 12:10

andybird123 said:
one of whom doesn't even have crossfire, very relevant

I don't at the moment but others with multi gpu have commented in this thread.

Rusty0611 said:
Not worth it - just ends up with pages and pages of twisting and turning .

If crossfire performance was that bad do you think Rusty (who butters both sides of his toast with regards to using gpu's) would still be using it? Let alone having just bought another 7950 for tri fire?

I am reading that right Rusty, you now have 3 7950's? :eek:

tommybhoy said:
Matt used CrossFire for long enough-he's very aware to the positive/negative workings of CrossFire hence his welcome advice in his helpful threads.

Yes he has. I've used 1900xtx xfire, 1950xtx xfire, 2900xt xfire and finally 6950 xfire. But what do i know?

As far as i understand it xfire gets gradually better with each generation. Hopefully in June it will take the final step towards becoming the complete solution.

Rusty0611 · 4 Apr 2013 at 12:16

No, only two. Where'd you get three from?

Can't use three on Z77 anyway...

LtMatt · 4 Apr 2013 at 12:19

Rusty0611 said:
No, only two. Where'd you get three from?

Can't use three on Z77 anyway...

Misleading signature is misleading.

Did you just add the &?

Bacon? · 4 Apr 2013 at 12:21

Wouldnt that be quad fore x-fire if he had 1 GB and 3 HIS cards

Catanonia · 4 Apr 2013 at 12:21

Thanks all. Looks like it will be fine.

Yes I am a BitCoin miner and expanding my kit to mine more. I do play games as well on the rig, but switch off the mining for that. So even after the mining, I will probably pay for the cards after 3 or 4 months.

I currently have 1 x 7950 and have another arriving. I was wondering on the possibilty of adding a 3rd to the rig.

Bitcoin mining is based on simple math algorithms and so the more processors you have the better. Hence the 7950 and other cards (AMD) have many many more shaders than a CPU has cores. My CPU 3930k does 10mhashes per second overclocked to 4.8Ghz, 1x7950 O/C does 600mhashes per second due to the 1800 odd shaders

I have taken a huge risk and ordered 2 butterfly miners, when and if they arrive is anyones guess. In the meantime this rig is mining and when ASIC miner hardware like the Butterflies and Avalons make GPU mining worthless I will switch them to LiteCoin mining which ASIC machines are rubbish at and continue mining BitCoins with my new Butterflies. Currently the only ASIC rigs available

To give you a clue, 3 x 7950 mine about 0.8 bitcoins a week and yesterday 1 Bitcoin was worth £90. It is fluctuating a bit with the euro crisis.

Anyways, thanks all. Was what I needed.

andybird123 · 4 Apr 2013 at 14:13

just looked, those butterflys seem very good value for money at 30 and 60 GH/s ?

Phixsator · 4 Apr 2013 at 17:31

There is really no point arguing over performance in games in this thread as its about Bitmining. Second when it comes to bitcoin/litecoin (or whatever coin) mining AMD cards simply dominates being roughly 5 times faster at the job.

https://en.bitcoin.it/wiki/Mining_hardware_comparison

So heres what to consider/expect when running 7950trifire for mining.

1) You do not need to enable trifire to utilize all 3 cards for mining. They just have to be plugged in and powered (even without a crossfire bridge)
2) They don't consume as much power running full throttle during mining as they do when gaming
3) 3x7950 @ 810 stock speeds should net you roughly 1500 mhash/s for bitcoin mining or 1500 khash/s for litecoins(which is roughly 9-10 litecoins a day atm for 24 hour mining). You may be able to squish more out of them.
4) For those who wants to get started I would consider litecoin mining and the Guiminer-Scrypt-alpha miner to do so as its much easier to start out with than fx cgminer.