As I’ve noted a couple times here in the past month, I impulsively bought a contemporary-architecture video card, a GTX 960, with the intent of using it in my Windows PC. On seating the card I was frustrated to note that it failed to operate, and have been engaged in a technical odyssey since then trying to troubleshoot the issue or to determine the extent to which the card may or may not be compatible with the machine.

This entry is going to be a link-and-data-dump consolidating my online discussions regarding the unit.

The card proper is the GeForce GTX 960 SSC 2GB, purchased from Amazon for under $200. The intended destination machine was a stock Inspiron 570 with an upgraded 500w power supply – the stock PSU for the machine was 350w and I bumped it when I bought my last set of GPUs, GTX 470s.

Here is the long narrative doc I wrote to clarify what tests I’ve run a few days ago. By the time I wrote this I had begun to try he card on one of my Mac towers as well, the current best-fit implementation but one with its own extreme limitations that need resolution as well.

(composed July 10, 2015)

GTX 970 narrative notes

First attempted install into i570

Useful link:

Thread appeared to validate card as OK based on power reqs, but card would not power on boot.

response notes probably higher power requirements

750w Corsair CS750M suggested PSU replacement.

Have add’l supercompact drive-bay PSU in hand originally sourced with the idea of driving 2x GT 470 in Mac Pro, not needed for that purpose. Mac Pro install is non-standard. i570 install may be wiser choice, certainly an acceptable test case.

After hitting power wall, began to experiment with GTX 960 in Mac Pro. In the meantime, correspondence with Nvidia established that the card was unsupported on the Mac hardware and that flashing it would void the warranty.

Kernel panic at boot with GTX 960 seated under Mavericks 10.9.x. Card is known as ‘Maxwell’, Maxwell wholly unsupported under pre-Yosemite OS X. Vanilla Yosemite install produces non-native video resolution to 3x monitors via DisplayPort to DVI cables, no reason to expect more out would also be supported.

Please note this is with stock GT 9500 / 120 seated. 120 is a fully Apple supported Nvidia card and as such displays what is known as the ‘boot screen,’ the apple and progress bar at startup or the boot drive selection at option-key startup.

No readily apparent downside to a Yosemite migration on the Mac Pro 4,1; even iPhoto is said to remain operable despite the hype of Apple migrating iThing services to new software packages.

Initial installation of Win 7 to discrete internal boot drive went smoothly. Both cards were recognized in Device Manager. GTX 960 appears with error triangle and is disabled. Error reports as Code 43. Diagnostic is step-through of disable, reenable, roll back driver, uninstall, reinstall. No resolution.

After several rounds of this the GeForce installer reported a problem with “MSI”, the remedy for which was to either rebuild MSI through a series of registry-type edits or via a clean install of Windows. I opted to start over.

Once back and up, the same issues generally presented themselves.

Using downloadable GeForce installers, installer numbered 3.41 is installed. On reboot, whichever card was disabled at GeForce install reports as enabled but video is available ONLY via GT 120. Additionally, Device Manager consistently installs more recent drivers for the GTX 960 than the GeForce installer.

(Update, a few days later the GeForce installers are fetching and installing the same drivers as WU, .5330)

In a Hail Mary, I rebooted without the GT 120 seated. The 960 came right up.

So to summarize:

  • To boot in Mavericks 10.9.x, the 960 must be unseated.
  • To boot in Yosemite 10.10.x, both the 960 and the 120 may be seated, and best results are obtained via Nvidia’s web drivers.
  • To boot in Win 7, both cards may be seated, but only the 120 will output video even when it is shown as disabled in device manager.
  • To produce output from the 960 under Win 7, the 120 must be unseated during a power-down cycle.
  • To observe the boot screen in Yosemite, the 120 must be seated.

This is clearly untenable; the two cards must be harmonized under Win 7 in order for this configuration to be acceptable.

SIDE NOTE: Bootcamp cannot maximize PCIe data transfer rates (it is limited to PCIe 1.x) and therefore the i570 is likely to produce higher throughput to the card. It would still be worthwhile to benchmark and experimentally run RoF on the MacPro prior to moving to the power upgrade procedure on the i570. if the i570 power upgrade fails, retrench with the expectation of selling the 960.

A random benchmarking site rates both the Mac Intel Xeon and the AMD stock chip in the i570 as roughly equivalent.

I need to post in on a Mac site regarding the conflict between the GT 120/9500 and the GTX 960 in Windows. I really think there should be a way to get the two cards to run concurrently.

Framerates in RoF with a direct-feed triple-screen setup at 3x 1080p (in either orientation) run mostly in the 50s and 60s with very occasional slowdowns under certain high-information-density conditions (flying low over an in-game town through mist with gfx settings on max). Overall a significant performance improvement is immediately apparent.

Shortly after I wrote this, I initiated a post on Dell’s community forums regarding the attempt to bring the card up on the i570. The same forums host a very detailed, insanely ambitious, highly-informative, but somewhat dated LOOOONG post on upgrading and modding the i570. The thread was written quite some time before the 900 series cards came out and does not address the issues I have been experiencing.

In my thread, a user suggests another power upgrade, to a 750w system that offers 20w on the PCIe power feeds (‘rails’). This sounds plausible but something about the suggestion led me to more carefully look at the power specs of the 960. As it turns out, the 960 has a lower power budget than the 470 it’s intended to replace, so while that 750w power supply *might* do the trick, it seems to me more likely that the problem is elsewhere. I’m reposting my contributions to the thread here.

(posted June 23, 2015)

Hi, after scrubbing forums here and elsewhere (such as Tom’s Hardware) I have not found a specific user testimonial to success running a GTX 960 in a power-bumped i570.

Is this card supported in the i570? Failing official Dell support, should it work anyway?

The master upgrade thread was posted prior to the 960 and is light on GPU details.

In general, user advice seems to indicate that given sufficient power, which 500w appears to be, BIOS update, and successful gfx driver uninstall, it should work.

What actually happens is: system powers on, all fans spin up, GPU fans spin up, no POST code beeps are heard, boot procedure halts at ‘checkpoint NN’ (A2, I think). I found a list of the Dell checkpoint codes and it indicated something about failure to start, I assume indicating a failure to initialize the GPU.

I use DDU to strip the gfx drivers. BIOS is current (A06, iirc).

I can boot the system without the card seated, with an additional antique VGA card in the lowest slot on the mobo and the 960 seated, and with the current GPU (gtx 470) seated. when the system boots with the VGA card and the 960 seated the 960 fans do not spin. I have not taken the time to examine the 960 status in device manager in this configuration.

I do not have another wintel machine to test the card in.

Signs seem to point to a bad card. GeForce appears to be willing to authorize an RMA. However, if the card won’t work in the machine, it may be wiser to send it back to the merchant rather than the mfr.

SpeedStep’s concrete analysis reads in part,

“You need an EPS12v 2.92 power supply. 500W is not sufficient.

You need 170W on the 3.3v/5v rails and 15 to 20W on the +5VSB rails and Minimum 375W on the 12v Rails.”

He also provides a detailed chart of the EPS12v 2.92 spec and a specific product recommendation, extremely helpful.

After I ran my power experiment with a discrete 450w unit, I posted an update to the thread.

Further progress or lack thereof.

First of all, thanks to SpeedStep for pointing at power as an issue. I’m not sure that’s the solution, however, after doing some investigation.

First, although the Mac does have a 900w PSU, and the actual max draw for cards has not been well-documented, the standard recommendation for dual hi-power cards is the implementation of a second PSU in parallel with the Mac PSU. I can’t recall the estimated top draw off hand but I think it was something like 300w, I could definitely be wrong. Given that the 960 comes up, and is described was a low-power card in comparison to others in the 900 series I wondered what its actual draw and PSU reqs were.

This PC World review notes that “The GTX 960 has a scant 120 watt TDP”. The GeForce 960 specs state that the minimum PSU is 400w.

The previous card I had seated on the i570 was a GTX 470. The linked specs suggest a min PSU of 550w, so it appears I was just lucky getting it to roll with the 500w unit. The wikipedia roundup on the 400-series cards indicate that the 470’s TDP is 215w.

(Update: I was misstating the specs, as will be discussed below. Nvidia’s specs do not call for a minimum PSU, they call for minimum available system power, which can be roughly estimated as PSU total power availability minus allocated power consumption prior to the card’s desired power draw. So that 400w min above more likely calls for a 550w PSU or more despite the card’s stated maximum power usage of 120w.)

So to summarize the data, the newer card appears to have a specification that calls for it to have considerably less need for juice than the predecessor card.

The 500w PSU currently installed does also have some deficiencies with regard to the specific available power that SpeedStep recommended, however. In particular, the PCIe jacks are rated up to 18w, not 20w. For the sake of experimental thoroughness, I poked around in my stack of parts and came up with a 450w PSU that had been acquired with the idea of implementing the dual-PSU mod to the Mac to enable dual 470s. This particular PSU was designed for use in the ride-along role and offers dual PCIe power feeds at 20w each. Given that the card would be the only draw on the additional PSU, I felt it should help to eliminate or confirm power as an issue.

As before, with the 960 seated and the on-board video disabled prior to seating and reboot, the system does not complete a boot sequence, and on next restart provides the “System halted at boot checkpoint [A2].” Slotting an antique VGA card into the PCI slot does allow the machine to boot with the 960 slotted, and consulting device manager results in the 960 being reported as active, installed, and working properly. Sadly, there is no video being produced by the card in this state.

There are some quirks in this i570’s startup sequence, the most notable being that it seems the USB ports are not being activated until after the initial startup screen, offering F2 and F12 setup options, has zipped past. This of course makes it impossible to get into these startup menus to examine them for video-device options.

In short, while it’s still possible replacing the 500w PSU with a beefier unit might resolve the matter, it does not appear that the card in and of itself requires the additional power by spec, as the unit in this power configuration exceeds the spec’s maximum power requirement and can be shown to do so with a higher TDP card.

I still have not found a positive anecdotal report that the 960 can work with the i570 under the current (and probably final) BIOS update, which was released in 2012. There are many instances of people asking this question online and being advised that with sufficient power the card should work; none of these interactions have produced a troubleshooting thread like this one, so I am inclined to think it should be possible.

Thanks again to SpeedStep for prompting me to take a closer look at the power issue.

So currently my suspicion is that the motherboard is experiencing some sort of issue which is preventing the keyboard from being recognized at boot. Earlier in this project I was very definitely able to get into both the F2 and F12 startup screens. The USB sketchiness is very odd – it seems to affect certain ports more than others, which could I suppose indicate intermittent physical connectivity. However visual inspection of the ports does not seem to support a bad connection from the port I/O unit to the mono. The port cluster is modular and does rely on a slotting system for mono contact, however.

One aspect of the i570 that I had not noticed previously and which normally is NOT a bad thing is the apparent lack of a built-in speaker. In this instance, it means that there are no boot-cycle status beeps, which is impeding my troubleshooting.

Just after I posted this SpeedStep replied with more information elucidating the writer’s perspective on power supplies and power specs. The upshot is that the manufacturer’s suggested minimum system power spec line refers to available power to the card after all other draws are accounted, not to the total available power provided by the PSU. So my 500w PSU may have as little as 354w available for the card after accounting for all other draws. This does not invalidate the power test conducted with the ride-along PSU, however, which certainly did have 450w available to the card.

As I was reading this and thinking about it I realized I had another thread to pull in here, concerning getting the 960 up on the Mac. MacRumors forums has a super-long and active thread about working with Nvdia non-EFI cards in Mac Pros, and I posted this in thread:

Hi, thought it might be beneficial to share experiences slotting a GTX 960 in a Mac Pro 4,1 late ’09.

First, as well-documented here, I had to install Yosemite to get any video out on the 960. Vanilla Yosemite provided video out even prior to installing the Nvidia web drivers, but not at my monitors’ optimum resolution. I don’t recall what the available resolutions were but they were all higher than the 3x 1080p I wanted; the video was scaled and usable if ugly. With the web drivers installed, 1080p was available. I have not tried installing the web drivers on the extant Mavericks boot volume and do not expect that to succeed but intend to try it for the sake of completeness.

Using Bootcamp to install a Win 7 boot volume has also succeeded, although the process was hairy and took several days of troubleshooting to master. I went through two complete clean installs of Windows before I could get the Nvidia installer to successfully implement the current drivers for the 960. I was able to get the correct drivers (.5330) for the 960 both by using Windows Update and by using the Nvidia installer in the end.

However, there are some major issues that remain unresolved.

First, the stock GT 120 (or GT 9500, the OEM EFI card), *must* be removed prior to booting into Windows or Device Manager will become confused and direct video out ONLY the GT 120. Disabling and/or uninstalling either card in Device Manager does not affect this; Device Manager can report either card as active and the other as disabled and the only video out is the 120. On reboot, one of the two cards will be reported as functioning normally while the other is yellow-triangle halted with, I believe, Code 43. It does not matter which card is shown flagged, there will only be video out from the 120. The only way I have noted to get video out of the 960 is to unseat the 120, which makes booting back and forth between Mac and Windows less than convenient.

Second, the Bootcamp / Win 7 audio issue which is customarily resolved by reinstalling the Realtek drivers under Windows does not successfully restore normal audio operability. I have been able to implement an audio solution by plugging in an external USB audio in/out module. This is actually an acceptable long-term solution for me even though it’s inelegant.

Hope this helps others running similar configuration experiments.

In-thread, another user suggested that preventing install of any Nvdia drivers for the GT 120 / 9500 would resolve the disabled 960 issue. I haven’t run a controlled experiment to verify that but am skeptical as I very definitely have seen the 120 come up as a generic VGA and with the 960 reported as active in Device Manager but in actuality with no video out. I should still see if I can get it to work as just keeping the 120 around in a static bag in case of emergency or booting back into Mavericks seems problematic at best. Reading the thread it does seem to be the most common response.