Two Radeon 5870 GPUs for OpenCL computing

Discussion created by akasheee on Jul 14, 2010
Latest reply on Jul 16, 2010 by nou


I am new in GPU computing. I have following two issues.

1.  I have two GPU Radeon 5870 GPUs and want to use OpenCL to accelerate some of my programs. The motherboard that I am using  is ASUS P6X58D-E LGA 1366 Intel X58 SATA 6Gb/s USB 3.0 ATX Intel Motherboard. Though the motherboard has 3 PCIe slots, I can use only two to plug the GPUs, as there are not enough space in the third PCIe slot. Now the usable two PCIe slots are very close to each other and thus if I plug these two GPUs in those PCIe slots, both the GPUs become hot. Actually then the space between two GPUs is about 0.5 inch and probably the GPUs cannot dissipate heat properly. Is it ok, to use these GPUs in this condition? I am scared, they might be damaged if I keep them in this condition.

2. Right now I removed one of the GPUs from the PCIe slot and using only one GPU for my computing. The monitor is also connected to one of the DVI port of this GPU. I am using Ubuntu 9.10 and I installed the ati driver 10.4, sdk 2.1 properly. They are working fine. But somehow the GPU is not detected and only cpu is detected for usable OpenCL device. I mean when I type ./CLInfo I got the following:

ashraf@apollo1:~/Desktop/ati-stream-sdk-v2.1-lnx32/samples/opencl/bin/x86$ ./CLInfo
No protocol specified
Number of platforms:                            1
  Platform Profile:                             FULL_PROFILE
  Platform Version:                             OpenCL 1.0 ATI-Stream-v2.1 (145)
  Platform Name:                                 ATI Stream
  Platform Vendor:                              Advanced Micro Devices, Inc.
  Platform Extensions:                   cl_khr_icd

  Platform Name:                                 ATI Stream
Number of devices:                              1
  Device Type:                                  CL_DEVICE_TYPE_CPU
............. etc.

Now my question is: can I not use the GPU (Radeon 5870) for computing if I connect it to the monitor for video output? If I want to use this GPU for computing, do I need to buy another ATI graphic card for video output? I have already an NVIDIA graphic card (9500GT, 512mb, Dual DVI) for video. Can I use this NVIDIA card (9500GT, 512mb, Dual DVI) for video output and use the ATI Radeon 5870 for computing?


I will really appreciate if someone can help me about these issues.

Thanks in advance