Does lower power usage of Maxwell card really save much?

[buggy]

My new machine was supposed to come with a GTX 750Ti, but they slipped in a GTX 660 instead as they are phasing them out, so I called and asked them to send the 750ti and I would return the 660. However, after reading the following comparisons I'm starting to wonder if I should keep the GTX 660 and return the GTX 750Ti (it arrived).

http://gpuboss.com/gpus/GeForce-GTX-750 ... TX-660-FTW
http://www.ocaholic.ch/modules/smartsec ... 79&page=16

It seems like the 660 outperforms the 750 by 11% on average and the only advantages the 750ti has is lower power usage (Maxwell) and support for higher digital resolutions (4096x2160 vs. 2560x1600 on the 660). I don't yet have a monitor that goes above 1920x1080 so resolution differences may not matter much. That leaves power use. Will the lower power use of the 750Ti translate into real savings (I use the machine at least 16 hours per day). I have a 1300W PS in the box so I'm not running into a limit there. If the power bill savings are not insignificant then the 750Ti would be attractive, but I don't know if anyone has an idea of this (based on average electricity costs in the Western US).

Are there any other reasons to keep the 750Ti over the 660? Is there some kind of speed boost that Maxwell cores exhibit exclusively in Octane that are not reflected in the card comparisons above (they used games to do their speed tests)?

I have two GTX 780 6GB cards, so this decision won't make a huge difference to my render times (although every bit helps). I plan to use these two higher-end cards exclusively for Octane and have my monitors connected to the third card (660 or 750ti), which will supplement the Octane rendering. I use 3DS Max version of Octane and not the standalone.
On a related note, is there a way to turn off the 780s when they are not in use (not rendering) and does the SLI bridge speed up or slow Octane down?

Overall I am very happy with the machine and the helpful advice I received here! It's phenomenally faster than the old PC I was using.

[glimpse]

hi, I would stick with maxwell.. (if vram is the same =) it will run cooler. eventually You'll get a bigger screen, So You can connect it (them) without any need to upgrade.

power savings is an issue here that is hard to translate into real world numbers, 'cos You're not running 100% 24/7, pluss efficiency curve PSU..-there's a lot of things to take into equitation if You want to do exact calculations. but if You're looking to have this card only for screen these numbers will be very small anyway..

p.s. What model do You have? It's nice that there's smaller versions of 750(ti). also even passively cooled ones =) as the noise of the rig could be reduced noticeably =)

[buggy]

Glimpse to the rescue again! You helped me make a good decision with my cards (2 x GTX 780 6GB) and so I'll take your advice on this one too.
The GTX 750Ti is made by MSI and has 2GB (the 660 also has 2GB). It says OC edition. I don't know if that means it is already overclocked or capable of being overclocked. The case has lots of fans but no water cooling so I don't think I will try overclocking things myself. The 750Ti has a fan so I guess that means it is actively cooled. There are no power connectors like the 780s and 660 have so it's getting all its juice from the motherboard.

I would be good to have the 750Ti card just for the cooler temps. The 780 that sits between the 660 and the other 780 runs 10 degrees hotter than the lower 780, so it may cool down a bit if it has a cooler 750Ti next to it instead of the 660. The 780 appears to get up to about 80 degrees during rendering (according the the GeForce Experience s/w), but I haven't pushed it much yet.

There's one remaining empty PCIe x16 slot, but the power supply is too close to allow a double-wide card. If I ever need more juice I could get one of the single slot cards that I've seen recently, but this thing is so fast I don't think that will be any time soon. I wonder if a riser ribbon can be used to connect to a double-wide card that I could put sideways above the other cards. . .

Before I take out the 660 I should benchmark it with the Octane greeble scene and then compare it to the 750Ti. I just disabled the 780s in Octane Standalone and used them for the monitors so that the 660 is only doing rendering. It hits 13Ms/sec with the greeble scene. I kept the camera in the default position as other positions give different readings. I'll do the same with the 750Ti. Is this the correct protocol for benchmarking?

Thanks again!

[glimpse]

get the 750 in the middle =) it is a bit shorter than the 780. You can lift up fan RPM a bit for those mounted in from to provide more air =) sometimes having a fan mounted in the side panel helps (if You have this option) as You give a bit more fresh air for GPU's. These non-reference gtx'es keep spinning the air inside the case, so a bit more of airflow is advisable..Anyway, back to the topic, split those two 6gigggers with 750 in-between =) You should be able to shave out like 5C at least =)

[buggy]

Just for interest's sake, here's some additional stats with the greeble scene before I swap out the cards:

The hotter GTX780 running at 83 degrees C: 30Ms/sec
The second cooler GTX780 at 73 deg C: 33Ms/sec

Both GTX 780s running concurrently: 63Ms/sec
Add the 660 and the speed goes up to: 76Ms/sec

GeForce Experience doesn't give me the temperature on the 660 (it's buried in the LED Visualizer tab, and only shows the 780s, even though the EVGA cards don't appear to have LED effects.) Perhaps there's better software out there for monitoring the cards.

[glimpse]

thanks for some numbers =)

I use GPUZ to monitor, GPUs as it gives way more useful metrics =)

& real temp to have small numbers down to the clock =)

[buggy]

That's a good idea. It had occurred to me to do that with the 660 but I might have forgotten about it by the time I got to the swap.

There are two fans in the front panel pulling air in and one at the back above the cards (in line with the CPU) as well as a ceiling fan (with vents at the top and with room for one more fan next to it). They are all large fans. If things get too hot I could add a pair of small ones in front of the grille just next to the cards. At what temperatures do you think I would be shortening the life of the cards?

I'll check out the GPU monitoring tools you suggest. There may also be something bundled on the EVGA card CD ROM, which I haven't installed yet.

[glimpse]

new GTX cards are rated or better said designed to run up to 80C be default under full load =) & I wouldn't advise running more than this to anyone who wan't to use cards longer..The reason? well, nVidia's pro line (read tesla) runs cooler. If they would think it's healthy to run cards at higher temps (24/7) they probably would made that (as loosing performance might negatively influence sales). GTX cards veer not made for 24/7 as game load fluctuate & thus doesn't torture the card for extended periods..

[buggy]

I just got back in and replaced the 660 with the 750Ti.

With just the 750Ti rendering it is at 11.24 Ms/sec.
If I turn on both 870s with the 750Ti I get 77.2, which is a pleasant surprise. I was expecting to take a bit of a performance hit going to the 750Ti from the 660, since there are fewer cores, etc. One contributing factor may be that the 780s are running a bit cooler (I think my office msy also be cooler than it was earlier). One is at 64 deg. and the other is still relatively hot (81 or 82 deg.)

Both GTX 780s running concurrently: 65.9 Ms/sec, so they are running slightly faster now that they are separated. I also had to take out the SLI bridge, so I don't know if this was a factor.

The bottom line is that overall performance is just as good as it was before, which is good news, and my power consumption will be lower with the 750Ti and things may be slightly cooler. I'm not sure what else I can do to keep the one 750 under 80 degrees. Perhaps I can stick an extra loose fan in between the card and the case panel and aim it into the heatsink at 90 deg. to the card fans.

It's back to work! (deadlines looming)

[MaTtY631990]

Hi

Can anyone tell me what you use to read the gpu temperature. I have gtx 750 ti, what temperature should this get to under full load.

Thanks