some 11 months ago, I bought a new graphic card for one of my PCs, in order to participate in GPUGRID crunching.
Unfortunately, I didn'd choose a really quick card: it was the NVIDIA Quadro K620.
Only 384 cuda cores, core clock: 1000MHz, memory clock: 900 MHz. 768 GFLOPS (single). No overclocking possible. Any "long run" task by Gerard took some 45 hours crunching time.

So, I made myself a Christmas gift and bought a GTX 750 TI - any bigger card would not have fit in my PC.
But okay, this card comes with 640 cuda cores, I have overclocked to 1233 MHz core clock and 1365 MHz memory clock. GFLOP figure as indicated by the manufacturer (Zotac) before overclocking is 1322 (single).

Taken all that into account, one would estimate that crunching time for a "long run" task by Gerard should be around 30 hours (or even less), right?

However, it is exactly same as before, i.e. some 45 hours. What a shame!!! How come?
Can anyone give me a reasonable explanation to this?
BTW, I am using the latest BOING version 7.6.9 (64bit), and the latest GPU driver by NVIDIA.

In fact, I was planning to also exchange my graphic card in one of my other PCs - this is a much bigger one, and I could put in even a GTX 980 - the price is around 600 Euros, but I would do it for GPUGRID, honestly. I am not a gamer, so I could easily do along with my old ASUS EN 8600GTS, which is an excellent card, but unfortunately, not able to do GPUGRID crunching.

However, the disappointing results from the recent graphic card exchange make we wonder whether I should really spend 600 Euros - maybe for nothing ???
Does a "long run" by Gerard take 45 hours in any case, regardless of what GPU is being used?

Can anyone enlighten me on these mysteries?

P.S. It just occurred to me: could this have to do with the fact that the PCIe-Slot is PCIe 1.1 x 16 (and NOT PCIe 2 or 3)?

NVIDIA Quadro K620: Only 384 cuda cores, core clock: 1000MHz, memory clock: 900 MHz. 768 GFLOPS (single). No overclocking possible. Any "long run" task by Gerard took some 45 hours crunching time.

GTX 750 TI: 640 cuda cores, I have overclocked to 1233 MHz core clock and 1365 MHz memory clock. GFLOP figure as indicated by the manufacturer (Zotac) before overclocking is 1322 (single).

Taken all that into account, one would estimate that crunching time for a "long run" task by Gerard should be around 30 hours (or even less), right?

However, it is exactly same as before, i.e. some 45 hours. What a shame!!! How come?
Can anyone give me a reasonable explanation to this?

Does a "long run" by Gerard take 45 hours in any case, regardless of what GPU is being used?

Can anyone enlighten me on these mysteries?

hello Zoltan, many thanks for your nightly thorough reply. All your explanations are very sound to me, and now I know a lot more about the technical environment and circumstances in connection with GPUGRID computing, and about the situation with my PC in specific.

What I did immediately thereafter was:
1) setting the SWAN_SYNC
2) reducing the percentage of CPU use from 100% to 95%. This immediately reduced the number of CPU cores used for other BOINC projects from 4 to 3. So, besides the GPUGRID task, now 3 other tasks are running at the same time, vis-a-vis 4 tasks before (however, for GPUGRID the status line still says "0.951 CPUs + 1 NVIDIA GPU" - is this okay?)

So, if I now add what is shown under "elapsed" and "remaining" time for the current GPUGRID task, it adds up to some 31,5 hours (a clear improvement over 45 hours as before). I am curious what it will be for the next task, when the settings I just changed have full impact on the complete task.

As mentioned in my previous posting, I am still thinking about exchanging the NVIDIA 8600GTS in one of my other PCs which has only 32 CUDA cores and is therefore not able to do GPU computing.
However, the most severe bottleneck I see here is again the PCIe 1.1 (16x) on my ABIT IP35 PRO mainboard. The processor is a Core 2 Duo E8400 @ 3,74 GHz, 2x2GB DDR2 800MHz RAM (probably the next larger bottleneck).
OS is Vista 32-bit; however, I will, in parallel, install Win10 64-bit (with dual boot) shortly.

So, after having read your explanations from last night, I am somewhat unsure with which new graphic card to replace the old one.
Originally, I had planned to buy the GTX 980 (which should hopefully work with my 450W power supply, having not really any other overly power-consuming parts in the PC).
However, particularly in view of the PCIe 1.1, would it make sense at all to buy a 600 Euro card which could then unfold only a fraction of it's power? Wouldn't I be much better off with a smaller Maxwell card like the GTX 950 or 960?
Or, in other words: under the given circumstances (PCIe 1.1), would a GTX 980 deliver a noticeably better result than a smaller card? Or would the differnce be just marginal?

Could you (or anyone else) please give me comments on this?

2) reducing the percentage of CPU use from 100% to 95%. This immediately reduced the number of CPU cores used for other BOINC projects from 4 to 3. So, besides the GPUGRID task, now 3 other tasks are running at the same time, vis-a-vis 4 tasks before

(however, for GPUGRID the status line still says "0.951 CPUs + 1 NVIDIA GPU" - is this okay?)

So, if I now add what is shown under "elapsed" and "remaining" time for the current GPUGRID task, it adds up to some 31,5 hours (a clear improvement over 45 hours as before). I am curious what it will be for the next task, when the settings I just changed have full impact on the complete task.

As mentioned in my previous posting, I am still thinking about exchanging the NVIDIA 8600GTS in one of my other PCs which has only 32 CUDA cores and is therefore not able to do GPU computing.
However, the most severe bottleneck I see here is again the PCIe 1.1 (16x) on my ABIT IP35 PRO mainboard. The processor is a Core 2 Duo E8400 @ 3,74 GHz, 2x2GB DDR2 800MHz RAM (probably the next larger bottleneck).
OS is Vista 32-bit; however, I will, in parallel, install Win10 64-bit (with dual boot) shortly.

So, after having read your explanations from last night, I am somewhat unsure with which new graphic card to replace the old one.
Originally, I had planned to buy the GTX 980 (which should hopefully work with my 450W power supply, having not really any other overly power-consuming parts in the PC).
However, particularly in view of the PCIe 1.1, would it make sense at all to buy a 600 Euro card which could then unfold only a fraction of it's power? Wouldn't I be much better off with a smaller Maxwell card like the GTX 950 or 960?

Or, in other words: under the given circumstances (PCIe 1.1), would a GTX 980 deliver a noticeably better result than a smaller card?

The 750TI was a workhorse at GPUGRID for years. Unfortunately, this has passed. Some batches of work can be completed and uploaded in under 24 hours. Many can not. There was one batch that would complete in just under 24 hours but the half hour to upload pushed it over the bonus limit. Overclocking would help for this one batch. I have a pair of them in a machine that got moved to a different project last month. They are still decent FLOPS/$ and FLOPS/W but a bit too wimpy for GPUGRID.

Looking at your second machine, I would ask you the following. What power supply is in that machine and do you want to purchase a new supply? I'll offer the following observation.

GTX 960 : 8 pin PCIe power plug. I bought one for my son for xmas and paid 20 US$ after rebate for a 420w power supply with the right plug.
GTX 970 : 2 x 6 pin PCIe power plugs. This is the most popular card on GPUGRID at the moment for good reason. Good FLOPS/$ and FLOPS/W. Great card.
GTX 980 : Still 2 x 6 pin PCIe power plugs. Good FLOPS/W but not so great FLOPS/$. The 970 is a better card if cost is a concern.

I do not like the adapter plugs that often come with cards. I would never, ever use them for a card you intend to use for GPUGRID. Make sure your power supply has the power plugs your card needs as shipped by the manufacturer.

I like linux for crunch boxes. They save the microsoft tax and return better performance than new windows versions. The disadvantage is it is more difficult to overclock the video card under Linux than under Windows.

Good luck and crunch on.

The 750TI was a workhorse at GPUGRID for years. Unfortunately, this has passed. Some batches of work can be completed and uploaded in under 24 hours. Many can not. ... They are still decent FLOPS/$ and FLOPS/W but a bit too wimpy for GPUGRID.

Looking at your second machine, I would ask you the following. What power supply is in that machine

If you install Linux or Windows XP, and don't crunch CPU tasks, then it is worth to buy a GTX 980 for your existing hardware.

Whereas I think it should be no problem to still get a XP CD from some source for new installation, I am wondering how safe this really is, since the system would be connected to the internet all the time. How did you solve this problem?

Just for my knowledge: for what reason exactly is your advise NOT to use such adapters?

Just for my knowledge: for what reason exactly is your advise NOT to use such adapters?

The reason is contact resistance: these power connectors don't have gold coating, still there's high currents go through them (240W/12V=20A).
The Molex connectors were designed for hard disk drives, which usually consume no more than 2A from the 12V and the 5V power supply pins.

Unfortunately, this PC is too small to put in any larger card than the 750ti.

There are smaller versions of the 970 that may fit into your case.
Here's one. http://www.newegg.com/Product/Product.aspx?Item=N82E16814121912&cm_re=gtx_970-_-14-121-912-_-Product

Look around for others. I know I've seen them advertised to fit into an iTX case.