Dell R610 server board not running cpu to its clock speed of 3.07Ghz

[c4onthefloor]

I recently picked up a dell r610 rack server and plan on using is for running a few private game servers. I got windows server 2012 installed on it and everything works just fine, besides the cpu actually going to its clock speed when its at load. I turned on cpu turbo frequency in the bios as well as cpu c states and the cpu still only gets up to 2.40 Ghz and also wont go above 78% cpu usage when I stress it in Windows. The cpu in question is a xeon X5675 that has a base clock speed of 3.07 Ghz. I also went through all the windows power settings and made sure nothing would hold the cpu back there. Anyone got an idea of what would cause this?

[c4onthefloor]

1 minute ago, Genwyn said:

Potentially a speedstep issue, try disabling speedstep in the bios.

Are you sure its not going full toaster mode and overheating?

Other posts on reading on this kind of problem seem to be power related more than anything. Theres also 2 versions of the motherboard in the r610, the first gen one is known to have issues with some of the xeon models power delivery.

ive tried both with speedstep on and off.  same result. Ive kept temps in check, and at 2.4Ghz and 78% cpu usage its at around give or take 55-60c across all cores. I dont think its temp related. I tested with a set of 2 original cpus that came with this board (xeon e5520) and it did the same thing. 78% utilization and I think it was around 1.8Ghz out of its 2.4 Ghz full clock speed. This is a dual socket board, but can also run with 1 single cpu which is what Im currently doing. 

[c4onthefloor]

Up

3 hours ago, Genwyn said:

Potentially a speedstep issue, try disabling speedstep in the bios.

Are you sure its not going full toaster mode and overheating?

Other posts on reading on this kind of problem seem to be power related more than anything. Theres also 2 versions of the motherboard in the r610, the first gen one is known to have issues with some of the xeon models power delivery.

I figured it out. this is the stupidest thing ive literally ever seen. If the server rack's side panel is off, the cpu wont go above 2.4Ghz, but with the side panel on, it goes right up to a happy 3.06Ghz. Dell must use some sort of sensor on the side panel and if its off them limit power or something. Who would have guessed that in a million years

[c4onthefloor]

2 minutes ago, Genwyn said:

thats definitely a weird one

i know some dell boards have chassis open sensors that keep them from even booting (most old precision boards wont power on if theyre not in a case), but to downclock the processor is a whole other level of strangeness

 

yeah I tested it like 3-4 times in a row just to make sure it wasn't a coincidence. its a really weird thing. But hey, I finally figured it out after like 10 hours of hair pulling all day. Mainly had the side panel off because im upgrading cpu and ram pretty soon here and I didn't really feel like putting the panel back on. Guess i'll make sure to keep that in mind with future dell products. Weird way of engineering something.