intel HD+CUDA

Hi, I got a pretty newbie questions, I am thinking to build a new workstation(actually for the first time), and was originally thinking about p67 mobo with two graphic cards one for video output and one for dedicated cuda computing(can i have one card that does both without any trouble???).

Now there comes new z68 chipset which allows you to use intel HD video output, so I am wondering if I can use the Sandy Bridge cpu+z68 for video output while at the same time have a dedicated graphic card for cuda computing.


The trouble with using the same card for both graphics and output is the watchdog timer that kills your computation after about two seconds.

As for the Intel, as far as I know, such a setup can work on a laptop, but on a desktop, the onboard gma is disabled by the motherboard if it detects a discrete video card.

I don’t think so. Some motherboards (e.g. Asus P8Z68-V Pro) even have a BIOS switch that allows you to use the discrete card and the integrated GMA in a dual-monitor setting.

For the moment, Z68 is the only way to have a dedicated CUDA card with a Sandy Bridge CPU without making any sacrifices. Any other setup cuts the PCIe bandwidth to the CUDA card in half.

I think most reports of the integrated GPU being disabled were for various pre-built systems by Dell, HP, etc. Some systems builders get a custom BIOS that disables the internal GPU when a discrete GPU is installed to avoid the confusion of potentially having two active GPUs. YMMV and all that.

Thanks guys.
So which configuration can have the best performance? two graphic cards(one CUDA, one output)+p67 or one CUDA card+z68+sandybridge?
Seems should be the latter according to hamster143’s point, is it?

There’s a registry key you can change that disables it.

If you want the best performance without breaking the bank, and if you don’t intend to overclock, get a Core i7 960 and a x58 mobo. (Or wait to see if Intel cuts the price of 970 any time soon.)

Current Sandy Bridge processors are best classified as budget/mainstream, and top of the line is still occupied by Nehalem. The Sandy Bridge LGA1155 socket is an evolution of old mainstream LGA1156. Both of them have dual-channel memory controllers and 16 PCIe lanes. The high-performance socket, LGA1366, has a triple-channel controller and 36 PCIe lanes. Intel is scheduled to start the roll out the Sandy Bridge-based replacement for its LGA1366 chips some time in Q4 2011.

Thanks, I never notice the bandwidth problem, and now it seems to me that two pci e 2.0 slots always share the same bus on z68 and p67, but on x58 they have separate buses.(Am I correct?)

I already bought the i7 2600k cpu, so now the only way to go would be z68, right? (Now, I am also thinking return the cpu and get an x58 and Nehalem cpu)

Hope you don’t get bored about these newbie questions, I’ve been f**king with my mind for a long time about which way to go!

Just get the z68 then, I guess. With p67/z68, there are three price levels:

  • Cheapest motherboards don’t even have a second PCIe slot or set it to x4 mode (quarter bandwidth).
  • The next level up allows you to split the bus traffic into x8/x8 (half bandwidth to each card).
  • The most expensive motherboards have an onboard PCIe switch chip which allows you to send full bandwidth to each card (but they still share the bus) and to use three video cards at once.

This does not matter much for video games, because those are designed to minimize PCIe traffic anyway, but it may pose problems in CUDA development and other things like grid computing.

Thanks, really learned a lot.

I think I will give z68 a shot(should be the medium class), and maybe upgrade to next generation X series mobo later if necessary while at the same time I got the money.