Trouble with dual quad Xeon system

[idata]

Hello,

I have the following problem, please help me to resolve it.

My system is:

- MBRD: S5000PSL (BIOS 0089, BMC 63, SDR 46, drivers: INF: v8.6.0.1008, LAN: v13.1) all performance settings in the BIOS are left at default.

- CPUs: 2x Xeon E5420 (2.5 GHz @ 1333 FSB), core multiplexing enabled, 8 cores at all

- RAMs: 2x Kingston KVR667D2D8F5/1GB FBDIMM, populated in bank A1 and B1

- VGA: Gigabyte GV-NX85T512HP (PCIe GeForce 8500 GT) in slot 6, driver: nvidia forceware v175.19 international whql 32-bit

- OS: WinXP Pro SP2 x86

- Other: 2x PCI-X and 2x PCIe x1 high performance video capture boards in slot 1, 2, 3 and 4.

The main function of this systrem is to run an application that continously captures analog video pictures from the installed video capture boards, convert them to digital data and store them on HDDs. The recording application is multi-threaded, it runs on single quad-core-CPU systems without any problem.

My problem is that the recording application somehow can't use the whole CPU capacity of this dual quad core system, only 50% of it and no more. All eight cores are running at 50% load and the application behaves like "no more CPU capacity is available", so it slows down. I can run other applications concurrently, they can use the rest 50% of the whole CPU capacity.

If I set the recording application's affinity in the task manager to run only on dedicated CPU cores, it can use the dedicated cores up to 100%. For expample, if I set the affinity to run only on the first four cores, these cores are running at 100% load, and the second four cores are in idle.

Thank you and best regards,

Janos K.