PSU for SLI doubt

By EEatGDL
Aug 7, 2013
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  1. Hi guys, this is my first time incursioning in multi-GPU setup territory. I'm about to build a rig with 2x GTX 650 Ti Boost and an i5 Haswell not unlocked -not going to OC it. To don't go deep into details about the rest of the hardware, my question is if this PSU is enough for what I'm intending even if it isn't certified for SLI or Crossfire (bottom section, look for the right model) but has 2 PCIe 6-pin cables; I live in Mexico so my buying options may differ a bit and the price point.

    I find this PSU decently priced but if you consider it is not enough I have room for a CoolerMaster 700W PSU that costs the equivalent of USD $15 more; I would prefer to save that money, but if there's no true use for the 600W option I'll go for it.

    It would be preferred if you have arguments based on personal experience.
  2. Blkfx1

    Blkfx1 TechSpot Addict Posts: 884   +171

    The 600W PSU will probably power the two cards. However, you will have little to no wiggle room. For crossfire / sli setups I'd recommend getting something with 700-800W of power. Plus, it would be in your best interest to get a PSU from a reputable brand. Some I know that make quality power supplies are : Corsair, Antec, and Seasonic. I believe some CM and Rosewill PSU's are also pretty good.
  3. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    I don't know what the power consumption test in Steve's review is from just the power cards or the whole system; my Haswell's TDP is of 65W. Thank you for your answer anyway I'll wait for more recommendations before making up my mind, I thought Thermaltake had a decent reputation [it was used some years ago in a SLI tutorial video by NVIDIA - back in the age of the 8 series and Crysis].

    I've had the same 430W Thermaltake PSU for 3 years now running my C2D and 9800 GT and I considered this brand as option in the topic-starter post because of the balance between price, power and personal use for some years.
  4. Steve

    Steve TechSpot Staff Posts: 1,325   +424 Staff Member

    That review was based on power draw from the wall. So under full load the entire system consumed less than 400 watts.
  5. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    So is that 600W PSU enough even if it's not officialy compatible with SLI? Thank you very much for the answer Steve, that means that while idle that power drawn was between the CPU, the GPU and the rest of plugged components, right?
  6. Steve

    Steve TechSpot Staff Posts: 1,325   +424 Staff Member

    600w will be sufficient and yes that was the idle power draw was from everything, entire system.
  7. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    Not worth going SLI with mid range cards, you're better off with a single GTX 760 which will have lower power consumption, run cooler and more importantly you won't have to deal with driver issues, motherboard compatibility and microstuttering.

    SLI/CF is only really for top end setups where one single GPU isn't enough.
    hellokitty[hk] and JC713 like this.
  8. Steve

    Steve TechSpot Staff Posts: 1,325   +424 Staff Member

    Correct.
  9. JC713

    JC713 TechSpot Evangelist Posts: 6,819   +884

    Well said.
  10. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    OK, I really don't get you. In the GTX 760 review the GTX 650 Ti Boost in SLI easily surpasses by much (20-30% more performance) the 760, based on almost costing the 760 twice the 650 Ti Boost here in Mexico... I don't see a smart buy here. Yes, drawing less power but also offering less performance than the SLI counterpart.

    I already have one GTX 650 Ti Boost, I can pay it twice in two different months (two payments) and buying the GTX 760 is paying 1.9 times the GTX 650 Ti Boost in the same month while getting 1.4-1.6 times the single GTX 650 Ti Boost performance; I repeat, in mexican prices.

    I did this for a reason: I would have to wait until September 1st to get a GTX 760/770 and then I wouldn't be able to enjoy it until december because of my career and having classes from 9 a.m. thru 8 p.m. from Monday to Thursday. But then investing almost the same amount of money but distributed in two months I get the chance of enjoy it for the last 2 weeks of summer vacation and the first week of classes when we basically do nothing important.

    But thanks anyway for your feedback and recommendations.
  11. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    If you're building a system from scratch and the GTX 760 costs 1.7x the 650 Ti Boost then I'd definitely go for the 760 or possibly 770 depending on how much that cost. However since you already own a GTX 650 Ti Boost then sure, getting another one is a good idea as it will be more cost effective than selling it and buying a 760/770.

    Almost all the performance graphs you'll see are average frame rates. However a single card setup which for example consistently outputs 50-60fps will give a better gaming experience than a dual card setup which outputs 70fps for the most part but has sharp drops to 30fps (which dual GPUs are prone to doing). Also you won't see the results of framerates above 60fps unless you have a >60Hz monitor. Then there's also the question of driver support where SLI might not work well or at all on new game releases.

    Not trying to put you off SLI or anything, Nvidia have done a great job in improving smoothness on SLI setups and in your situation it sounds like a good idea. Just make sure your motherboard supports SLI.
    JC713 likes this.
     
  12. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    Yeah slh28 I totally understand your point but I barely have 2 months with my job and couldn't save much money, half of my first payment was gone in paying college.

    The thing is I couldn't wait for my third payment like I mentioned before because I wanted to make use of the rig some time and because I built it from scratch trying to balance performance and mid-term investment -I'll invest on it these 2 months and then again when Broadwell is released, it will take a while-. And to save posting the whole rig later which now I think I should have posted on the first place, here it goes what my budget could afford:
    *Chassis Coolermaster K280
    *Mobo ASUS Z87-A
    *Core i5-4570S
    *16GB of DDR3 RAM Kingston HyperX @2400MHz (CL11)
    *GTX 650 Ti Boost 1GB from Gigabyte
    *Keyboard Logitech G105

    And so I lost room for a better single GPU in this month. I kept my 1TB HDD, my 430W Thermaltake PSU temporarily, mouse and screen. Next month I buy the PSU and the other GTX 650 Boost. I knew about the possible complications with SLI and new games, profiles, etc. which I'm willing to try and see if it isn't that big headache overall but my plan B was buying a cheaper 7 series chipset mobo with an Ivy Bridge Core i3, 8 GB of RAM @1866 MHz and a GTX 770 without the possibility of SLI.
  13. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    In all honesty I think plan B was a better build (with an IB i5 processor) but what's done is done. There's no benefit in upgrading to Broadwell from Haswell, your next CPU upgrade should be a DDR4 compatible one (I.e. Skylake, Haswell-E) and even then you'll probably see minimal benefit in terms of gaming.

    Try to find a Corsair, Seasonic or XFX PSU around 750W if you can, investing in a decent PSU now will mean you can run pretty much any dual GPU setup in the future, otherwise you might find you need to upgrade again if you get a 600W one.
  14. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    Yes, I think I can make room for the 750W PSU next month. As for plan B having i5, I would have to sacrifice something to compensate the price difference.

    Skylake is far away and very probably will use another socket [so there's no way to prepare now for that]; Haswell-E... simply unaffordable. That's why I said mid-term, when I read the news about Haswell-E of course I wanted it, but "wanting doesn't get"; I'm pretty sure that I would rather buy an used car [I don't have any] than build a rig with Haswell-E -not even the 8 cores, native PCIe 3 and quad channel DDR4 memory can lure me into that.

    My idea is to upgrade without building from scratch again from the i5 Haswell to an unlocked i7 Broadwell and OC it, then get a decent SLI with propably GTX 870's by then; that will give me time to pay college, get a car, complete my professional practices and other personal investments out of computers [I'm just 3 semesters away from graduating, and maybe with an Intel engineer salary and internal discounts I can accelerate the process and maybe even consider Haswell-E or Skylake by then].
  15. JC713

    JC713 TechSpot Evangelist Posts: 6,819   +884

    You could have cut back on the RAM and saved $50-$100 and put that toward a 760 or a i5 4670K.

    You have to understand this though: SLI has many issues like slh said, and those issues are a huge pain. If you can, always go single GPU.
  16. St1ckM4n

    St1ckM4n TechSpot Evangelist Posts: 3,448   +619

    SLI issues are mostly a pain if you're running brand new games. OP doesn't have money for a new single-GPU card, so it's safe to assume he hasn't got $80 to spend on new release games. Playing a year old $15 games off Steam is perfectly fine with the matured drivers.

    I've had SLI before, and it really wasn't all doom and gloom. It's a valid tactic, especially for OP.
  17. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    That's right St1ckM4n, I'm aware about the problems with new releases without specialized SLI profiles, microstuttering and those other issues; and as you say I don't have brand new titles, I'll get some new on december vacation. I'm preordering with my credit card XCOM: The Bureau in Steam but I don't think I'll have time to play it until december, I'm interested in taking advantage of the rewards.

    Besides that I just want to play nicely Crysis 2 online, right now I'm struggling with DX9, lowest settings and getting sometimes a minimum of 8 FPS during an online match [average of 32 FPS] and some less demanding titles for the time I have left.

    And finally about the RAM: is just OK for me even without playing. I can eat up 8GB/8GB in my laptop without opening a game, just my workspace (lots of programs, tabs in browsers, MATLAB for digital signal processing, etc.) during classes and the virtual machine for my job; and that's only me. At home, there are 5 users fighting for some time on the PC, everyone leaving their sessions opened to not loose what we're doing until we all start logging off at night before turning it off (seriously, that PC gets used about 15 hours a day continuously), besides my brother and I virtualize as a job requirement for quick system recovery because we're exposed to all kind of content and simply we want to save the money in AV -if something gets messed up in the virtual machine, we just boot from the copied virtual disk, erase the messed virtual disk and create a new copy from the previous copy. So yes, 16GB is just right for us, I'll admit the premium is the frequency.
  18. JC713

    JC713 TechSpot Evangelist Posts: 6,819   +884

    Yeah, one drivers mature and profiles are added, SLI is fine.
  19. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    Hello guys, I took your advise about the PSU and I have 2 candidates (one of them will be bought during the end of this week): one 850W and 1000W (both Cooler Master Silent Pro M2), they are competing with each other because the latter is in promotion, I could save some money from video card, and I'm getting some extra cash later this month.

    I don't want the quick "go for the 1000W option", because if I won't be ever using it near its full potential; I would prefer to save that money. I plan to stick with the winner for 5-6 years since both have a 5-year warranty; it will take a while to get to the target PC config which I estimate will be by the end of 2014, this are the target specs when I'm done for some years ahead:
    *i7 "K" Broadwell or Skylake (I'll decide it when the time comes) slightly OCing it
    *2-way SLI 780s or 880s [will buy the latest available on the second half of 2014]
    *2 SSDs in RAID 0
    *2 HDDs (4 TB total)
    *Maybe a Blu-ray drive or the current DVD-RW
    *Water cooling for the CPU Hydro H80I
    *Either the current 4x4GB DDR3 @2400MHz or DDR4 if I go for Skylake
    *2 120mm chasis fans

    I used 3 different calculators estimating a power consumption of ~730W averaging them with what exists right now, all recomending a 850W option, and for what I've seen in the 780 Palit SLI review, the review's whole system didn't draw more than 500W. Taking all this in consideration, give me a hand.
  20. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    If they're the same price then obviously get the 1000W one. Just bear in mind that Broadwell/Skylake are process shrinks so will consume less power than current CPUs. From the build you've described a 750W PSU is enough.
  21. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    The 1000W has a $30 USD equivalent discount that makes it a $40 USD of difference instead of the normal $70 difference.
  22. JC713

    JC713 TechSpot Evangelist Posts: 6,819   +884

    750-850W will be enough like slh said.
  23. Blkfx1

    Blkfx1 TechSpot Addict Posts: 884   +171

    And, even at 850W you have a lot of breathing room. I run two 7950's with around 20% OC's on them and I doubt I'm close to maxing out its potential wattage.
  24. EEatGDL

    EEatGDL TechSpot Booster Topic Starter Posts: 267   +47

    OK, I'll pick the 850W option; maybe pay the little difference as the 1000W but for the 850W 80 Plus Gold one. Thanks.
  25. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    Yep that's probably a good idea, 80+ Gold PSUs will generally be of better quality and if you're keeping it for several years you'll get some of the price back through the power bill.


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