Why is my Mac Pro 5,1 with GTX 780 slower on some games

[Demigod Mac]

Hey MVC,

Got my 780 back from you.
Just wanted to be absolutely-positively-certain before making a move.

I can plug both 6 pin cables into the card (straight from the Mac's logic board), with one of the 6 pins going into the 8 pin slot, no adapters needed at all?

Thanks, and I can't wait to try this baby out.

 

[flowrider]

^^^^My GTX780 flashed by MacVidCards has two 8 pin connectors. Both my six pin cables are plugged on the right side of the connectors.

Plug it in, you'll luv it.

Lou

 

[MacVidCards]

Here are photos of the 2xSATA to 6-pin adapter.

I'm using a 6-pin extension to reach from this adapter to the card.

If you flip over the connectors in the top left photo, you will see that there are only 2 wires connected to ground side.

Those 2 wires lead only to the sense pins that turn on card. So instead of 4 total pins with ground, only 2 would be connected to anything.

So if that connector was only one plugged in, the 8 pin plug would "think" all was fine but card would be starved for power. Perhaps this is what happened when you got those half speed results.

The fact that this plug is included with PC cards and when plugged in this way in a Mac Pro leads to double current being pulled from just 2 pins while 2nd 6 pin only gets normal load makes these plugs especially dangerous for Mac users with PC cards.

 

[RoastingPig]

.

 

[Tutor]

I have a 2010 Mac Pro w/2x 2.4GHz quad-core Xeons. I recently replaced the ATI HD5870 with an EVGA GTX 780 (03G-P4-2781-KR). On some benchmarks & games, it's much faster (2-4x). On some games, it's actually much slower though. Has anyone seen this?

Some maybe-relevant info:

• Stock non-EFI GTX 780
• OS X 10.8.5 with Cuda 5.5.25 drivers from here
• 24GB RAM & 512GB SSD
• System info shows "Graphics: NVIDIA GK11x 3072MB" -- I've never been able to get it to say GTX 780
• Diablo 2 is solid at 60fps with all settings maxed at 1920x1080
• LuxMark crashes (I believe with an OpenCL error). I'm using version 2.0 - can't find the link for 2.1beta.
• Borderlands 2 is about 45 fps at 1920x1080 with everything maxed (with dips to 30 fps). It runs between 50 & 60 fps with all quality settings at off/low. I can't remember the speed it ran on the 5870, but it's not tons faster with the 780 (I seem to think it's roughly the same).
• Guild Wars 2 slowed to about 30fps with settings maxed at 1920x1080 (with dips below that and very little variation with lower quality settings)

Anyone have any ideas why some things (games) aren't seeing any speed boost?

I don't game in OSX and here's my 1 cent.

Sounds like there could be an OGL related issue with the Nvidia driver (but less likely because some of your games are much faster) or, more likely, an issue with how the miscreant games were coded and how your Nvidia card handles (or mishandles) that code. Use Google to see if you aren't alone and for possible solutions.

Regarding Lux Render, its coding is biased in favor of AMD cards (a logical explanation that I was given is that the author had only an AMD card to develop and test the application). Also, there could be a problem with your OCL driver or its installation. I experienced that kind of problem with Lux Render in Windows - solved by uninstall and re-install.

On Windows, if I were having the concerns you've described, I'd uninstall both any AMD drivers and any Nvidia software. Then I'd re-install the Nvidia software to get rid of any conflicts and get a clean GTX 780 install package. Other OSX gamers may be better able to help you with getting that clean install type of environment in OSX if it is possible.

 

[Demigod Mac]

It works!

 

[Demigod Mac]

First benchmark results!

 

[Tutor]

First benchmark results!

That W3680 is a much better CPU for a gaming platform than the E5620. Is that the same system as referenced in post # 1?

 

[Acceleroto]

First benchmark results!

Dude, nice! Go, Titan!

If you flip over the connectors in the top left photo, you will see that there are only 2 wires connected to ground side.

Those 2 wires lead only to the sense pins that turn on card. So instead of 4 total pins with ground, only 2 would be connected to anything.

So if that connector was only one plugged in, the 8 pin plug would "think" all was fine but card would be starved for power. Perhaps this is what happened when you got those half speed results.

The fact that this plug is included with PC cards and when plugged in this way in a Mac Pro leads to double current being pulled from just 2 pins while 2nd 6 pin only gets normal load makes these plugs especially dangerous for Mac users with PC cards.

I definitely see your point. I attached a photo of the 2x SATA to 6-pin adapter I'm using. It has one of the SATA plugs connected to 2 of the pins and the other SATA plug connected to the remaining 4. All 6 pins are wired, but if one of the SATA plugs wasn't seated correctly, it'd definitely cause issues.

The SATA plugs themselves don't actually stay seated well at all, so it would have been easy to bump one loose when routing the wires of even closing the case.

The 2x 6-pin to 8-pin adapter that came with the card actually has wires connected to every one of the pins in all 3 of the connectors. It looks like it's designed to share the load equally between both of the 6-pin connectors. Likewise, however, if one of the 6-pin connectors wasn't seated correctly, it'd be bad.

I believe the 8-pin adapter is fine, but I'm not happy with the 2x SATA to 6-pin adapter. I'll do some looking for a better solution. Overall, however, using the stock 2x6-pin plugs and 2x SATA plugs to power the GTX 780 seems like plenty power. (That is, if the 2x SATA ends actually draw power from all 3 of the 12V pins.)

Thanks a ton for all the help everyone. I'm really happy to have this thing humming!

 

[Acceleroto]

That W3680 is a much better CPU for a gaming platform than the E5620. Is that the same system as referenced in post # 1?

No, Demigod has different CPUs than I do. Just lowly 2.4's here.

 

[Tutor]

No, Demigod has different CPUs than I do. Just lowly 2.4's here.

My mistake. I missed the "2x" in front of your model. Since you have a dually with 2.4's, overall it is still a good system (my 2009 Mac Pro had dual 2.2's originally). You can upgrade it to dual 5680s or 5690s if you need more speed. Keep in mind, however, that their production will cease at the end of this year; so as time goes on it may become more difficult to upgrade. Also, as did Demigod, you might want to have MVC lay his hands on and bless your GPU with greater compatibility for your favorite OS. Moreover, if you compare your GTX 780's CUDA-z Core specs to those of Flowrider's, you see that your clock rate is depressed by about 105 MHz, which may be enough to explain your complaint - yet another reason why you may want to let MVC do the due.

 

[Acceleroto]

My mistake. I missed the "2x" in front of your model. Since you have a dually with 2.4's, overall it is still a good system (my 2009 Mac Pro had dual 2.2's originally). You can upgrade it to dual 5680s or 5690s if you need more speed. Keep in mind, however, that their production will cease at the end of this year; so as time goes on it may become more difficult to upgrade.

Yeah, after spending lots of time this year during WWDC prying info out of various Apple employees about the new Mac Pro, I decided to look into upgrading my 2010 Mac Pro instead. Even if I get a 2013 Pro, I'll still use my old one in my business. Once OpenCL is working on my 780, I don't know that I'll need the CPU bump for most of what I do (it's mostly a development machine). The SSD & extra RAM were great additions. It looks like the 780 is too.

It's definitely time to consider it though. If processors are still available, I plan on waiting until after I launch my next game early next year.

 

[Acceleroto]

780Ti....I'm still in the return window for my 780. Hmmmmmm.