Slow rendering using draw instanced

Hi all – I have a client who is attempting to use draw instanced but is getting unexpectedly poor performance, roughly half the performance of equivalent rendering without using the draw instanced feature. This contradicts what I’m seeing on my system, so I’m suspecting a driver issue or lack of hardware support.

My client is using NVIDIA Quadro cards (tested on FX1700M, FX4600, FX4800, and FX5800), using device drivers rev 180.51 or 180.60 on CentOS Linux.

I’ve been testing on GeForce 9400 with WinXP, and GeForce 9800M with Vista, and have not seen the issue. On my systems, using draw instanced results in about a 30% performance boost over the equivalent rendering without draw instanced.

We are using the same code.

Is anyone from NVIDIA able to confirm my suspicion that this might be a NVIDIA Linux driver issue? Thanks.