Seasonic S12 600w 1900 Crossfire prob's

[raju]

HI,

I added another fan to my pc yesterday, and upon banchmarking noticed that Firefly Forest 3D Mark 06, was causing the system to freeze. Before adding the fan I could pass the benchmark. Basically this brings the total amount of fans in my system to 7!! I also run to WD 250gb in raid 0, so with the 1900's in Crossfire this is a very heavy load for the psu, when overclocking the psu just can't take it.


I ran a series of tests @ different voltages with and without overclocks:

1) I first increased the voltage to my overclock CPU speed, so the vcore was .025 higher @ 1.5v. This caused the benchmark to run a fraction of a second longer, before freezing.

2) Went into bios lowered the overclock speed, by 60mhz, kept vore @ 1.5v. Benchmark still froze.

3) Returned to stock speed with 1.5v, still failed.

4) Decreased vcore to 1.4v, still failed.

5) Unplugged 2 case fans from the 12v rails, the benchmark passed.

Basically the Seasonic is a great psu, but when yoyu have a heavily loaded system, it is unable to supply the current demand. Now I know why I have been having trouble getting stable over 2.7ghz, I knew there was more in the cpu.

I'm using the DFI CFX3200 with a 4800+ CPU and 2gb Corsair 3500LL Pro.

I'm quite interested in the upcoming Silverstone ST75ZF, it has four 12v -18 amp rails.

Are there any other power supplies I should consider, I will be overclocking so stability is a must, the psu should be reasonably futureproof.

I have also looked at the Xclio 750w, but it lacks the 8 pin connector that my motherboard can take advantage of. I like the psu because it is modular.


The PC&P supplies are just too expensive for me to consider, so I'd like something in the range of the units above. The disadvantage with both of my current favourites is that they have not been tested by anyone trusted yet.


regards
Raja

Any suggestions?

[krille]

To be honest, I think you're expecting too much from your Seasonic S12-600. As you're saying, you may very well be pushing it too far. A new Seasonic S12-650 "Energy +" 80PLUS certified PSU is slated to come may/june and there will also come a new Seasonic M12-700 PSU (with an extra 60mm fan) sometime later, probably june/july, if you're interested in getting a more powerful, yet low-noise PSU that is.

The upcoming Silverstone ST75ZF should handle your current setup, I'm quite sure. There is a thread about it here (http://forums.silentpcreview.com/viewtopic.php?t=31049) over at SPCR where a Silverstone official participates. You could probably ask him about it.

Good luck!

~ Kris

[maratus]

S12-430/500/600W PSUs aren't 12V-orientated,

But M12-700W is (I hope S12 Energy+ will too)

M12-700W is modular also, you may like it, and you can take 650W+ (672W Max) from 12v combined
(Quad 12v rail virtual separation 18A max each, 56A Max combined)

S12-Energy Plus should have even tighter rails (lower ripple) due to non-modular leads.

[raju]

Hi thanks for the replies,


I am having a hard time believing the specs for most of these psu's now,


four 12v rails supplying 18amps each would equal 864 watts alone.

that's not including 5v @ 30 amps and 3.3 @ 28 amps.

Meaning that simultaeneous max current draw from all rails is not possible. When you have a heavily loaded system that is overclocked, it does happen, I never used to think the power would actually be required, but I have now found otherwise.


Raja

[Steensen]

The FSP Epsilon 700W (not any othe FSP, it has to be the Epsilon) will be able to supply your system.

The quad 12V rails of 15A each, is acrually capable of supplying 20A each, but not all at the same time. (i.e one rail 20A, one rail 11A and two rails 15A).
Just remember, it can "only" supply 680W from the 3.3, 5 and 12V rails (last 20W is from 5V st.by, minus 12 and 5V.), but it is capable of supplying all 680W from the 12V alone.

The problem with 99% of the dual rail PSU's out there is, that they have connected the two PCI-E power plugs to the samt rail, and thus a X1900XTX CF setup @stock load is already overloading the GFX rail (X1900XTX draws 10.5A from +12V rail, meaning 2*X1900XTX =21A >20A --> overload), and eaven more so when OC'ing starts on the GFX.
The fans is propperly also connected to the GFX +12V rail, and therefore you experience pass without the two fans, but freeze with the two fans.

The FSP Epsilon 700W (and 600W for that sake) supplies the heavy users from sepperate rails:
12V1: CPU1 (Pin 1-4 int the ATX+12V plug)
12V2: PCI-E2 + CPU2 (Pin 5-8 int the ATX+12V plug)
12V3: Peripherals
12V4: PCI-E1

Thus meaning, that the PCI-E1 has 15A (20A) for its disposal, where as the PCI-E2 has to share the 15A (20A) with the second CPU (a dual core doesn't draw much/any power from pin 5-8.), and that might be a problem in some systems (603, 604 and 940 systems), but shouldn't be any problem ind 939, AM2 and 775 systems.
The reason why I says the rails can supply 20A each, is that the rails are build with 20A mosfets, but the spec. is just reduced, to make the PSU more flexible (see example earlier).

[raju]

Thanks for the info.
I've heard good things about the FSP, both from you and a review site who I have personal contact with, it's bettered by only one psu atm but that's in a different price league. There are other supplies on the horizon, I'd like to wait for a month or so, until there are some user reviews and good site reviews. I may add more hard drives in the future, so will probably go for an even larger supply than 700w, I'll keep a close eye on the upcoming Silverstone. Failing that I may have to invest in a PCP 850w beast.

Raja

[zicl]

i have also had problems with my x1900 crossfire setup and the Seasonic 600W

basically i could not run any 3d apps when i have all my HDD, DVD, fans etc running, let alone clock my system any.

I agree this problem must be the 2 PCI-E connection being on the same rail. therefore i am also going to go with the 700W FSP unit.

It just shows how much power these 1900 cards take, i ran my 2 x 7800GTX sli on an OCZ 520W unit no problems with high clocks and all my HDD etc connected, still i wouldnt go back :D

[raju]

I've just ordered the 900w Tagan, will see how it works out this weekend.

[WildEye]

Could you post a review about that 900w when you get it?

Esp regarding any noise it makes/ how loud the fans are?

:toast:

[raju]

I'll have a go, though in my system it may be hard to pick up the noise anyway..

[nn_step]

Not to be an ass or anything but what made you think 600w was enough for Crossfire, especially since each card pulls over 120w?

[krypt0]

Personally I'd go with a single rail psu especially for dual gpu setups. Seems people consistently have problems with power on dual vid card rigs when using multirail psu's. The marketing for those is intentionally confusing and the atx spec is not ideal for such configs unless you're looking to drop a ton of cash on something like the PCP&C units. You can't forget it's not just about the wattage rating. For these systems it definitely more about amperage and efficiency.

Edit: Have a look at the ocz powerstream 520 and the silverstone st56zf

[raju]

nn_step, it was one of those mistakes that we have all made, I read up on the web and everything seemed ok at the time, I'm not overly concerned. My post here was not to knock Seasonic at all, it was only to bring attention to the situation to prevent others from repeating my error. In the right system the Seasonic has many merits.


Well I've already got the Tagan now, I can confirm it did have the cold boot issue with my DFI CFX3200, I managed to get around this by using a 0.22uf cap in parallel with my case power switch. So I'd agree with the posts above single rail psu's are the way to go at present if using dual gpu's. Even the PCP&P 1000w units have had the startup issues with a certain motherboard.

Everything else works fine for me with the supply, and I can confirm it is quiet, but obviously you need to mod your system to make it work. Until Tagan can rectify the matter at the hardware level I'd look elsewhere, unless modding is no big deal to you.


edit: unfortunatley upon further testing I found the cold start cap fix does not work, I've dropped Tagan an email to see if they will revise my unit, otherwise I guess I'll have to rma.

[Wam7]

Don't know which one you ended up getting but the FSP Epilson range has proved time and again it can handle the strains of SLI/CF better than most PSU's.

[raju]

Hi,

I got the 900w Tagan, the first one had a problem on start up due to the current being out of spec for the whole batch TAGan shipped to the UK.

I now have a new 900w Tagan, it's working great. Will test further before writing anything else though.

Regards
Raja

[krampak]

S12-Energy Plus should have even tighter rails (lower ripple) due to non-modular leads.
Lower ripple? that's possible? :)

This is my SeaSonic SS-600HT (new Rev. F3BLR) on my dual core (and single x1800xt):

http://www.la-tartana.com/hardlimit/SS-600HT-F3BLR/2006-05-16-12h22-Volt12.gif

CPU it's at just 1.32v but it's still impressive.

[psupef2k]

If I am running only 1 1900XTX, should the S12-600W be ok for my system? I recently started experiencing cold boot issues (1 long 3 short beeps), but it works after a reset or 2, and all benchmarks pass fine. I think my issue is memory or motherboard related, but I Could be wrong. Obviously I would buy a new PSU if doing crossfire, but I figured I would be ok with this one in single card configuration. Any thoughts?

[Mankz_91]

Anr't the 700W epsilons meant to be very unstable?

surely a 900W targan PSU would do anthing as would a 850W PCp&C?

[raju]

The Tagan is running fine, it's nice to have the extra wattage available without having to worry.

[Mankz_91]

yeah, but it costs the earth, but if you can afford a £400 GPU, 150ish isn't that much

[raju]

exactly..

BTW, I have 2 of those GPU's ;)