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Topic: Powercolor 7990 - page 3. (Read 14782 times)

legendary
Activity: 1554
Merit: 1222
brb keeping up with the Kardashians
June 05, 2012, 12:26:36 PM
Agreed.  I'm keeping my eye on Computex for the (alleged) 7990 announcement.
hero member
Activity: 518
Merit: 500
June 05, 2012, 12:25:19 PM
Forget about this monster.

Where is my tame 7990 Huh

With FPGAs and ASICs anyone buying this overpriced crap is a mugu / fool !
legendary
Activity: 952
Merit: 1000
June 05, 2012, 08:54:55 AM
Jesus, 3 8 pins and an external power supply jack.

That's not a DC jack. That's the big red OC button seen in the other pictures.
hero member
Activity: 658
Merit: 500
June 05, 2012, 08:48:19 AM
Jesus, 3 8 pins and an external power supply jack.
legendary
Activity: 1344
Merit: 1004
June 05, 2012, 06:30:36 AM
Now thats the porn I came here to see.
member
Activity: 66
Merit: 10
June 05, 2012, 05:20:40 AM
legendary
Activity: 1274
Merit: 1004
June 02, 2012, 11:01:09 PM
Quote
I can count them on a motherboard though.

Never could. I don't also understand the difference between say 24 phases and 8+2 or something like that for mobos.

I think the question here is go 7970x2 or reference 7990s ( if these even exist ) Huh

But as always, Wikipedia knows.

http://en.wikipedia.org/wiki/Buck_converter#Multiphase_buck

Say you have a 10 phase power supply that runs at 100kHz. That's one switching every 10us. Now, instead of switching them all at the same time, you'd switch one at t=0, one at t=1us, the next at t=2us ... and the last as t=9us, before the cycle repeats. It's multiphase because they're the same supplied, but they're out of phase with each other, similar to how 3 phase AC power lines are 120 degrees out of phase.
sr. member
Activity: 369
Merit: 250
June 02, 2012, 10:06:56 PM

I don't also understand the difference between say 24 phases and 8+2 or something like that for mobos.


The more phases, the less voltage spikes.  You know, when cpu's are oc'd to 1.4v.. a voltage spike could fry it.
hero member
Activity: 518
Merit: 500
June 02, 2012, 08:33:57 PM
Quote
I can count them on a motherboard though.

Never could. I don't also understand the difference between say 24 phases and 8+2 or something like that for mobos.

I think the question here is go 7970x2 or reference 7990s ( if these even exist ) Huh
legendary
Activity: 1344
Merit: 1004
June 01, 2012, 10:32:29 PM
Not to sound like a huge n00b, but what is a "phase"?

google it.

in an extremely dumbed down way of putting it though, more phases = better Tongue

I believe more is supposed to fight any sort of voltage droop from high loads. Usually doing a higher power load will reduce the voltage consequently, unless you have higher quality power hardware. you can see this easily with any sort of hardware monitor program and a stress tester. chances are if you run a stress tester program, your 12v sensor will drop a couple of percent, maybe less if you have very good quality power supply. The same happens to cpu core voltage. if you have bad power hardware on the motherboard, your core voltage will droop under stress (my evga 790i sli ultra had this problem bad. lost nearly 0.08v when under full load on quad core overclock)

If you couldn't tell, I don't know what constitutes as a "phase" either Tongue I can count them on a motherboard though.
legendary
Activity: 1274
Merit: 1004
June 01, 2012, 10:31:26 PM
Not to sound like a huge n00b, but what is a "phase"?
Very simply, think of it as 17 power supplies in parallel. It's a little more complicated than that (the different phases in the switching power supply switch at different time to help reduce ripple and whatnot), but that's basically what it does.
rjk
sr. member
Activity: 448
Merit: 250
1ngldh
June 01, 2012, 10:29:59 PM
Not to sound like a huge n00b, but what is a "phase"?
Since power regulators are cheap, they are usually run in parallel instead of using one or two really big ones. The number of parallel regulators is the number of phases. Usually, each regulator chip also has it's own control signal pin from the voltage (PWM) controller, so they can be controlled individually for efficiency.
hero member
Activity: 896
Merit: 1000
Seal Cub Clubbing Club
June 01, 2012, 10:15:54 PM
Not to sound like a huge n00b, but what is a "phase"?
legendary
Activity: 952
Merit: 1000
June 01, 2012, 10:01:18 PM
17 phases !?!??!?!?!?!!

With 500+ Watts running thru there, i'm assuming they prolly had to just to keep the temps down.
rjk
sr. member
Activity: 448
Merit: 250
1ngldh
June 01, 2012, 09:46:43 PM
17 phases !?!??!?!?!?!!
sr. member
Activity: 369
Merit: 250
June 01, 2012, 03:40:05 PM
#98
...Same MH/s, same space in the case, but better airflow.
...Same MH/s, less space in the case, but better airflow.

No, I said it right. I'm talking about keeping that 4th slot open for airflow. If you did take out the extra slot, it would be less space.

2 slots (7970) + 2 slots (7970) = 4 slots with bad cooling.
3 slots (7970x2) + 1 slot (for airflow) = 4 slots with better cooling.
3 slots (7970x2) + 0 slots (for airflow) = 3 slots with bad cooling.

Oh, ok.  That's kind of what I was hinting at o.o
legendary
Activity: 952
Merit: 1000
June 01, 2012, 01:18:24 PM
#97
...Same MH/s, same space in the case, but better airflow.
...Same MH/s, less space in the case, but better airflow.

No, I said it right. I'm talking about keeping that 4th slot open for airflow. If you did take out the extra slot, it would be less space.

2 slots (7970) + 2 slots (7970) = 4 slots with bad cooling.
3 slots (7970x2) + 1 slot (for airflow) = 4 slots with better cooling.
3 slots (7970x2) + 0 slots (for airflow) = 3 slots with bad cooling.
sr. member
Activity: 369
Merit: 250
June 01, 2012, 11:33:34 AM
#96
...Same MH/s, same space in the case, but better airflow.
...Same MH/s, less space in the case, but better airflow.
legendary
Activity: 952
Merit: 1000
June 01, 2012, 11:28:10 AM
#95
I don't think a price has been released yet for the 7970 X2. Considering its size and the amount of energy it will chug, I would think of buying one if a waterblock and more narrower rear IO bracket was released.

I am wondering if it is worth buying a dual Radeon 79xx card now or wait another 6 to 7 months for the second generation of GCN.

The advantage this has over dual cards is cooling. To take up 4 PCIe slots in a MB, you can either have 2x double slot 7970s crammed together with bad cooling, or this triple wide with a slot below for airflow. Same MH/s, same space in the case, but better airflow.
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