PC won't post. (Sort of)

[YoshiHDify]

Hi all,

I have a computer that suddenly won't post. It had worked for a while already.

The computer is an upgraded old HP pavilion desktop that's about 4 years old.

The only things that are still stock is the cpu i5-750 the case and the motherboard.

All Ram replaced now running 2x4gb + 2x2gb (12gb) total.

Gpu replaced to hd7870

Psu replaced to aywun 500w

Things I troubleshooted:

GPU works in another pc

PSU should be sufficient as I jumped the power from another pc to power the 7870 and it still won't post

RAM should be fine see below

What makes the pc post:

Replacing the Gpu with a low end passive nvidia card ... So ram is ok??

These characteristics are repeatable.

I'm really confused as to what the issue might be.

Any ideas guys?

Thanks in advance,

Harry

[,,,,,,,,,,,,,,,,,,,,,,,,,,]

You have your answer, the PSU.

[Amazingasian]

I will bet that your PSU isn't actually delivering 500W.  Replace it with a quality Seasonic or XFX unit and see if that helps.

[YoshiHDify]

You have your answer, the PSU.

But when I jumped the power from another PSU to try power the 7870 and it still wont post.

[,,,,,,,,,,,,,,,,,,,,,,,,,,]

But when I jumped the power from another PSU to try power the 7870 and it still wont post.

 

Connect the other power supply as a whole. Not just to the GPU.

[2001blader]

Get a new PSU. Even if its not the issue, you shouldnt trust that PSU. Its using a lowercase w instead of a capital one, meaning it can output a max of 500w, but not constantly,

[YoshiHDify]

Connect the other power supply as a whole. Not just to the GPU.

Thing is my other PSU is actually in another system, which has all the cables zip tied. I actually moved that entire computer up next to the HP to troubleshoot. That's why I'm reluctant to move everything.

That being said I do believe that if the 500W PSU can power everything with a low end card it should hold its own when it's powering no gpu (when I have all the auxiliary pcie power supplied from another PSU) all it had to do was power the pcie lane.

I originally was suspecting the PSU and in a way still am. But it seems as though people here are pretty certain that's the fault? If so I will just buy a new PSU and save some hassle.

[,,,,,,,,,,,,,,,,,,,,,,,,,,]

Thing is my other PSU is actually in another system, which has all the cables zip tied. I actually moved that entire computer up next to the HP to troubleshoot. That's why I'm reluctant to move everything.

That being said I do believe that if the 500W PSU can power everything with a low end card it should hold its own when it's powering no gpu (when I have all the auxiliary pcie power supplied from another PSU) all it had to do was power the pcie lane.

I originally was suspecting the PSU and in a way still am. But it seems as though people here are pretty certain that's the fault? If so I will just buy a new PSU and save some hassle.

 

That PSU is awful. The amount of wattage doesn't mean it's good. There are a lot of contributing factors, but right now I"m busy playing rocket league!

[YoshiHDify]

Replaced PSU with Corsair 650W. SAME result. Put GTX970 in HP, boots. Put HD7870 in HP, no boot. Put HD7870 in another PC, boots.

What the hell is going on?

[TrifectaIII]

Replaced PSU with Corsair 650W. SAME result. Put GTX970 in HP, boots. Put HD7870 in HP, no boot. Put HD7870 in another PC, boots.

What the hell is going on?

Hmm this is definitely sounding like one of those extremely difficult to explain problems...

 

Was there anything different about any of your installs?Like maybe, you used a different port on the 7870 when it posted correctly in the other PC? Anything at all that could be the difference between the hardware combos that do boot vs the one that doesn't?

[YoshiHDify]

Hmm this is definitely sounding like one of those extremely difficult to explain problems...

 

Was there anything different about any of your installs?Like maybe, you used a different port on the 7870 when it posted correctly in the other PC? Anything at all that could be the difference between the hardware combos that do boot vs the one that doesn't?

Unfortunately not, there is only one PCIe slot in this motherboard. Even tried resetting the BIOS to no avail.

[jackchipm]

The way that you could find what the problem is is to take everything off of your mobo then one by one but the components back on to the mobo, starting cpu then the ram and then the gpu. If it does not post with only the cpu then it is the power supply.