CPU dead or something else?

[forteh]

Hi,
I just got an i5 750 as a replacement for my i3 530 from eBay, sold as tested and working. Put it into my machine last night and it wouldn't power up or post. Some leds flash on the motherboard and the fans momentarily spin up, however it doesn't beep or post.
Took the chip out and checked all the socket pins with a loupe and they look ok, put the i3 back in and it posts/boots fine including the 4.6 ghz overclock.

I tried all combinations of ram and gpu with the i5 to no avail, even just the cpu on its own have the same result with no beep codes. The cmos was reset multiple times.

Is it possible that the psu might not be giving the cpu enough juice on startup? The i5 uses 22w more than the i3 but I wouldn't have thought this would manifest as a problem posting? My psu is an old ocz modstream 520 which whilst pretty long in the tooth these days has never given me any problems in the past. I can probably borrow a modern psu from work to test but is it likely or am I clutching at straws? The eBay seller does have a returns policy so not the end of the world but it is annoying.

Any advice would be much appreciated

 

[pooley]

I'd be inclined to return tbh..

 

[forteh]

That's my thinking but wanted to ask the opinion about the psu not giving enough as that is the only thing I couldn't be sure about. I will see what the seller says

 

[joeyjojo]

22 W is a paltry difference, I think if your PSU was that close the edge you'd know about it!

Does your motherboard definitely support it? BIOS update needed?

 

[forteh]

Bios is latest and according to gigabyte it is fully supported since bios F4.

Board is a GA-H55M-Ud2H rev.1 bios F11 (latest)

CPU support list

I figured that the peak power shouldn't be an issue but have read somewhere that the core chips needed a later atx spec that supplied more current on initial startup, however it has run my i3 for almost 5 years now.

edit: the seller is accepting the cpu back with a refund and will test it, if they can repeat the problem they will refund the postage as well

 

[joeyjojo]

I figured that the peak power shouldn't be an issue but have read somewhere that the core chips needed a later atx spec that supplied more current on initial startup, however it has run my i3 for almost 5 years now.

That's interesting, didn't know that.

 

[forteh]

Don't ask me to tell you where I read it though! Something to do with atx2.2 to atx2.3 or something along those lines. Might be a red herring though as I don't know what standard my psu is or how to find out.

edit: from wikipedia
I may have misread the higher starting current thing

ATX12V v2.3

Effective March 2007. Recommended efficiency was increased to 80% (with at least 70% required) and the 12 V minimum load requirement was lowered. Higher efficiency generally results in less power consumption (and less waste heat) and the 80% recommendation brings supplies in line with new Energy Star 4.0 mandates.[18] The reduced load requirement allows compatibility with processors that draw very little power during startup.[19] The absolute over-current limit of 240 VA per rail was removed, allowing 12 V lines to provide more than 20 A per rail.

My psu may be atx2.3, from reviews my psu get 75-80% efficiency, not sure if that can be related though. I do have a single 12v rail at 28A so maybe it is, I think it would have been around 2008 that I bought it from ocuk.

 

[ALXAndy]

Silly question, you did reset the board to default before inserting the I5 yes?

4.6ghz out of an I5 1156 would be pushing it somewhat...

 

[forteh]

Yup, cleared the cmos before putting it in, cpu is now in the hands of royalfail