Upgrade HP Compaq Dc7900 Ultra-Slim Desktop PC

[DEATH-DFC]

Hi,
This question is for NonSequitur777 but I don't know how to ask him a question direcly (or even if it is possible on this forum to contact someone...) and the topic he opened in 2021 related to my question is now closed. Can't reopen it or anything.
I'm upgrading an HP Compaq dc7900 USDT just for fun. And I have a "few quick" questions about that.

So I've had a dc7900 USDT since... maybe 2008-2009... and for a long time now I was thinking of upgrading it just for fun. At the time, I had already installed an Intel SSDSA2M80G2GC SSD (Intel X25-M Series). Needless to say, it's been a long time. I also added 4GB (2GB originally I think), installed Windows 7 64bit (originally there was Windows XP 32bit on this machine), then Windows 8, 8.1 over time and finally Windows 10. And before installing Windows 11 I wanted to upgrade it a little more.
So I recently came across the topic of NonSequitur777 on this forum while doing a search and decided to start updating again.

So before going any further I wanted to know if there were ears to listen to my question(s) on this subject?

[NonSequitur777]

@DEATH-DFC,

Yea, I'm glad I saw your post in the proverbial forest!

Please, go ahead, ask/fire away.

Kind Regards,

NonSequitur777

[DEATH-DFC]

hello, thank you for your reply.
So I (re)started upgrading this dc7900 based on the experience you had. I upgraded the processor to a Q9550S, I wanted to upgrade to 8GB of RAM as well, but I'm not going to do like you and put in an external graphics card. Instead I will try to put an NVME SSD (M2) with an mPcie to M2 type M adapter. I already have the adapter and I just received the M2 SSD. All I have to do is test it.
The problem is the RAM. I had some doubts about being able to put 8GB because the informations available on the USDT model was contradictory. But as you managed to put 8GB so I ordered 2*4GB of RAM.
Unfortunately they didn't work at all! I don't know if it's because they weren't supported by the chipset or because they were damaged. However, these were RAM sticks supposed to be compatible, 16 chips, etc. This type of RAM stick is not cheap but I came across a good promotion... obviously it was a failure. I was able to return the 2 RAM sticks so that's not the problem.

So the first question is: what exactly did you put in for 4GB RAM sticks? Are there any particular constraints or have I really come across a defective batch? (or a scam...)

Best regards

[NonSequitur777]

@DEATH-DFC,

The RAM I used was one 4GB DDR2 PC2-6400, 800 MHz, non-ECC, Unbuffered SODIMM, 200-pin Dual Rank (2Rx8) RAM stick of Samsung M470T5267AZ3-CF7, and one 4GB RAM stick of DDR2 PC2-6400, 800MHz, non-ECC, Unbuffered SODIMM, 200-pin Crucial CT51264AC800.C16FC:

Seems to me that either 2 x 4GB of the Samsung or Crucial RAM sticks should be compatible.

Kind Regards,

NonSequitur777

[DEATH-DFC]

ok thank you,
I will try to find the same model. I suppose the ones I received were defective... I bought on ALieExpress and I'm starting to have doubts about the quality of the products (but we'll see later). I am attaching a photo of the RAM sticks.

Another question is how Windows displays CPU percentage. On this model, since... Windows 8 I think, the CPU never exceeds 90-92% max in the task manager. But in CPU-Z for example it can go up to 100%. I have other "old" PCs like an Optiplex 745, Hp Compaq dc2400 MT, HP Pro 3010 MT... and as far as I remember, under Windows 10 or 11 none of these PCs have the same display problem . Perhaps there was this problem on the Optiplex 745 (not sure...) but by switching it to a Q6700 the problem no longer appears. I have read many forums and help, Some seem to say that it comes from power management, a Windows bug, etc. I remember changing some settings in the BIOS on this subject to try to resolve the problem, but without success it seems. At one point the PC systematically restarted 1-2 seconds after being stopped and I had to unplug/replug it so that it stopped restarting. I had to do a BIOS reset to permanently stop this behavior.
Do you have the same problem with CPU % display?

[NonSequitur777]

@DEATH-DFC,

An HP Compaq dc7900 Ultra Slim Desktop is compatible up to 2 x 4GB RAM.  It stands to reason that the RAM you bought is probably defective.  I don't recall having the same problem with CPU % display, but then again, I haven't used this desktop for quite a while.  As a matter of fact, my HP Compaq dc7900 USDT UserBenchMark entries (along with other 3+ year old benchmarks) are gone.

Kind Regards,

NonSequitur777

[DEATH-DFC]

ok, for the RAM I found the same model Samsung M470T5267AZ3 - CF7 on ebay. I took 2 of them, it's not really "cheap" but hey... I'll see.
Another question is related to the NVME disk that I am going to put. I installed and formatted it to test it. Already I'm rather disappointed because I don't know if reading the SMART type parameters are accurate, misinterpreted or something else, but under ChrystalDiskInfo it tells me that the disk has a status of 98% (the Intel SSD from 2008 is still at 100%!) has already served 78 hours, started almost 200 times, and has already read and written some 3.5TB!! Which makes me doubt the quality of AlirExpress products once again... if the reading are correct, what could this disc have been used for! And it was supposed to be new!
But what bothers me the most is the speed of the mPcie port. It is supposed to be version 2.0 on one line. Which should give 5GT/s. Except Hinfo64 tells me that the disk is at 2.5Gt/s! And ChrystalDiskMark actually tops out at around 215MB/s! I wonder if it's the mPcie > M2 adapter that does this but I have doubts because it seems to me that it's a simple pass through
So, what transfer speed do you have with the graphics card you installed on the mPcie port?

[NonSequitur777]

@DEATH-DFC,

For the most part, I've been fortunate ordering parts via AliExpress -and I probably just jinxed it.

Anyway, give me a day or so to dust off my mothballed HP Compaq dc7900 USDT, install the WLAN-slot connected PCIe x16 riser/adapter card, and see what we get.

Kind Regards,

NonSequitur777

[NonSequitur777]

@DEATH-DFC,

All right, here we go: hooked up an RX 6600 graphics card, updated software, etc. and ran UserBenchMark: HP Compaq dc7900 Ultra-Slim Desktop Performance Results - UserBenchmark:

Kind Regards,

NonSequitur777

[DEATH-DFC]

ok, so if we look at GPU-Z results it is indicated that your card is PCIe x8 4.0 capable and that it is currently in x1 1.1

v1.1... so either there is also a problem with your mini pcie card or the dc7900 really limits to version 1.1. However it is clearly marked 2.0 in the doc and moreover on HWinfo it clearly indicates that the PCIe port is 2.0