GPU fail in HP Compaq DC7900

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bentremblay

bentremblay

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/*RESOLVED*/
I thought the PC working fine meant that PSU was pulling its weight. I assumed insufficient power would be obvious by either Blue Window or failure to boot. Not so: the PC worked fine even though the GPUs had not come to life.
Thanks to all for your help.

In my experience these Radeon GPU have been plop.fizz easy to install; just Plug&Play.
Went from 5770 to 5850 to 7870 in my first build, not a problem. And likewise plop.fizz with a 7870 in my most recent build.
But now this: no joy with GPU in this box. (I use this half-height HP for my work; 95% text).

E8400 dual-core 3GHz ... can even run games like Gettysburg and AirLand Battle.
But then there are some games that load but run with only like 8FPS ... unplayable, really.
I figured what the heck, pop in one of my spare GPU. So tried that (after making some harsh changes on the case).

The 5850 was very unhappy ... screeched like a banshee so I shut down quick after confirming no video out except for VGA.
The 5770 made no such complaints, but ... again, only the standard VGA out working.

My concern is this: I could go out and buy a half-height card but then ... then what?!
I don't know why this failed. So it might just fail with a new card also.

Is there something about this CPU and/or mobo and/or chipset that makes the box incompatible with GPU?
That would be disappointing.

TIA to any geek who sees the problem.
--ben
Click to expand...

 
Solution
unknownofprob
In terms of where your coming from the CPU/MoBo/ChipSet wouldn't be the factors but what I would consider are would be the Power Supply and the motherboard BIOS.

To before I'm pointing out the significant power draw difference between the cards, as it seems from your tests that the more power you draw, the worse the effects/performance gets.

To get more disturbing information I'm seeing these specs for your HP pre-built:

Screen_Shot_2015_11_16_at_7_13_06_am.png

Screen_Shot_2015_11_16_at_7_13_34_am.png


first off does the included power supply even have any power connectors? If it does it by far is not capable of supporting a 5850, let alone a 7970.
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Martell1977

Martell1977

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A half-height card is really only about the space in the case aka. form factor. The GPU is the same except for maybe the clocks as being smaller, the cooling solution is often smaller as well. However, the half-height cards are often lower end and don't use much power.

It's quite possible that the PSU can't sufficiently power those cards.
If it's the small form factor version here:
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c01570344
you likely have the 240w PSU and that is the issue.
 
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bentremblay

bentremblay

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I wrote "screeched like a banshee so I shut down quick after confirming no video out except for VGA."
I also wrote "again, only the standard VGA out working."

Given that ... I don't know what to tell you.



 
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bentremblay

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I don't see how this relates to the failure mode.

But ... see above: everything was running fine, which I confirmed using the VGA out to do a normal shut-down.
So ... PSU was not sufficient? w/respect, this is voodoo logic.
 
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bentremblay

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Both worked just fine ... which is why they're still on the shelf.

The system was running just fine, both times, with both GPU in place, which I confirmed by normal shut-down using the VGA out.

I described how my 5850 and 5770 reacted. I pointed to my 7870 only as an example of how a 3rd GPU worked perfectly well ("plop.fizz" and "Plug&Play") in my 2 other PCs.

 
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unknownofprob

unknownofprob

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In terms of where your coming from the CPU/MoBo/ChipSet wouldn't be the factors but what I would consider are would be the Power Supply and the motherboard BIOS.

To before I'm pointing out the significant power draw difference between the cards, as it seems from your tests that the more power you draw, the worse the effects/performance gets.

To get more disturbing information I'm seeing these specs for your HP pre-built:

Screen_Shot_2015_11_16_at_7_13_06_am.png

Screen_Shot_2015_11_16_at_7_13_34_am.png


first off does the included power supply even have any power connectors? If it does it by far is not capable of supporting a 5850, let alone a 7970.
 
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Solution
Martell1977

Martell1977

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Read:
http://www.tomshardware.com/answers/id-2754540/advice-half-height-graphics-card-pls.html

The power supply (PSU) cannot power the cards you are trying to put in it. You get basic VGA output because they are getting just enough power from the slot to give you that. But they are not "working fine". You might think it's "voodoo logic" but a 240w PSU is nowhere near enough.
The thing about half-height cards is that they are lower power, that is why they are able to have smaller coolers and be half-height...
 
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bentremblay

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BIOS is locked. Looked around for some way to un-lock it but found none.

Uhhh ... I'm puzzled: I wrote about no such results because there were no such tests. Both failed, period.

This is absolutely fabulous data. It gives me hope!

I wonder why folk bring up that other card. I wrote about how I tried with 5770 and 5850.
In any case, just what the doctor ordered.

Thanks for your fullsome solution.

 
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bentremblay

bentremblay

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Evidently that's the case. I thought I was certain about 5770 being low power.
Oh woa, I never said that they were working fine. I wrote that they worked not at all.
I wrote that the PC was working fine. Huge difference.
Now here's my mistake: I assumed that insufficient power would have affected the PCs performance. Which, for some reason that escapes me, it did not.
The boards failed to produce video; the PC was "working fine".
I mis-read the symptoms. I anticipated a basic system-wide failure w/insufficient power. I was wrong.
 
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unknownofprob

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Should have also mentioned the Locked BIOS, HP tends to do this to prevent system modification (some parts still have the ability to be upgraded - Graphics card seems will work). Reason being if you can't upgrade it, your forced to buy a new desktop sooner then if you were to upgrade it.

"Uhhh ... I'm puzzled: I wrote about no such results because there were no such tests. Both failed, period."

You mentioned the 5770 worked (only just by the sound of it), and the other two did not. Since the 7970 has a much higher power draw then the 5850 (99W), and the 5850 is 43W above that of the 5770, the PSU is under a lot more strain, and the effects should be greater the more load you put on the already overloaded PSU.

"This is absolutely fabulous data. It gives me hope!"

Can't tell if sarcasm but it does, depending on your current motherboard power connector (and case size) a PSU upgrade would be the solution, however for that system with it's locked Motherboard BIOS I wouldn't go too far into the upgrading aspect.
 
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bentremblay

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Why is there not an obvious link to OP? too bizarre.
No, for sure didn't say 5770 worked. If 5770 worked, why would I have posted this?
Anyhow, going to post / ask about using external PSU.
 
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bentremblay

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;-)
I shouldn't grin. It's kinda tragic. But I hear you.
Forgive me for the dawg-ugly potential alternative I came up with:
I have a 450W vanilla PSU on the shelf.
Soooo I plug that in and use that for 5V to GPU. I think it's quick / easy / ugly. (When I finish my re-build/transition of game PC [Phenom 960 4X3.5GHS to I hope Intel i5 xxxxK 4Xxxx] this won't matter.)
Simply plug in the 450PSU, seat the GPU, use the external power ...
... am I overlooking something deadly?

I don't think BIOS is in play. Would be for OC, for sure, but for this? Again: I can't see what I can't see / dunno what I dunno, but seems straight-forward.

p.s. face-palm on not realizing it was PWR short-fall. I really did assume the box would just fail to boot properly.

 
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