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Old 06-25-2020, 04:22 PM   #805
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Smile Dell OptiPlex 790 for a Gaming PC

So in the Winter of 2017, I acquired a bunch of used/broken desktop PCs from a shop that was cleaning out its storage. Most of them were from the Core 2 Duo and Athlon II era or older. There was one “modern gem” among them, though (at least by my PC standards ): a Dell Optiplex 790 MT (“mini tower”) with a Core i5 CPU.

For a few years, I kept the system mothballed, thinking I still wouldn’t need a Core i5 for the games that I played currently (Fortinite, CSS, CSGO, Dirt Rally, and some others.) And for the most part, this was true. My EVGA 780i-SLI / OC’ed Core 2 Duo Q6600 build (posted here) was still holding up in the previously mentioned titles. However, Fortnite with its constant updates really started bogging that PC down to the point the game was unplayable (FPS in the 20’s on average, frame time full of spikes lasting up to 1-3 seconds and sound stutter – a sign of severe CPU bottleneck.) Moreover, I started getting into frequent instability issues with the Q6600 build (I suspect a dying nVidia chipset on the motherboard.) On top of that, the heat output from the OC’ed Q6600 with the GeForce 560 GTX GPU was a little too much for hot summer weather.

Therefore, it was time for something new(er)… but something that still had PS/2 ports, because apparently I’m still stuck in the stone ages with my oldschool mice and keyboards with no intent of changing those any time soon.

The Dell Optiplex 790 fit the bill. The Optiplex 790 not only has two PS/2 ports, but also even a serial port (now even I don’t need something that legacy! ) Ports aside, I picked up that system completely barebones – only CPU, motherboard, a single 2 GB stick of DDR3 RAM, and the stock Dell 240 Watt PSU. No video card or HDD included. The case was also missing a side panel and damaged… but more on that in a bit. I can’t complain, of course – it was a freebie PC after all!

When the warm summer weather of 2019 rolled in, I had enough of the hot-running and crashing EVGA 780i-SLI mobo. I took the Optiplex 790, threw in a spare 250 GB HDD (WD Blue), 4x 2GB Samsung DDR3 RAM (to test all RAM slots), and a better PSU. I then proceeded to install Windows 7 Pro (as per the COA on the case) in order to test the system. All tests passed and the stock CPU cooler actually seemed good enough for the job. After this, I swapped the RAM to 2x 8 GB modules and put a Diamond Radeon HD6570 2 GB DDR2 video card. Then, time for games – namely Fortnite first, because this one seemed to be the most CPU heavy. It ran very well, with consistent frame time and 45-60 FPS (capped at 60 FPS) – more than double of what I was getting on the Q6600 build, despite it having a much superior GTX 560 video card. Of course, for the HD6570, I did have to drop the render scaling to 50% on a 3D resolution of 1280x960. This shouldn’t be surprising, though, given the HD6570 is a rather weak card with only 8 ROPs and 24 TMUs. But even running the same graphics settings on the GTX 560 and Q6600 didn’t improve performance – still had terrible frametime and low FPS.

So, compared to the OC’ed Q6600 build, the Optiplex 790 system really was flying. Not only that, but it gave me ZERO issues during any time of the setup and testing process (unlike the EVGA 780i-SLI mobo, which took a lot of convincing to get it to work with 8 GB of RAM.)

Eventually, I upgraded the GPU in the Optiplex 790 with the Gigabyte Radeon HD6850 I rescued (posted here), and BOOM - my new gaming PC was born! Less power-hungry and faster at the same time.

Current specs of the Optiplex 790 system:
CPU: Intel Core i5-2500
RAM: 16 GB DDR 3 PC12800 @ 667 MHz (2x 8 GB Samsung M378b1g73eb0-yk0 sticks)
Video: Gigabyte Radeon HD6850 Windforce with 1 GB DDR5 [GV-R6850C-1GD rev 1.2]
HDD: single 250 GB Western Digital Blue (7200 RPM, 3.5”, SATA)
Optical: Samsung Writemaster DVD-RW of some kind (currently disconnected, but still installed in the PC if needed. Reason: it’s complicated.)
PSU: 350 Watt continuous / 400 Watt max. FSP Group AX400-PN recapped
OS: Windows 7 Professional SP2

For keyboard and mouse, I stole the Gateway G9900H and Logitech M-S69 combo from the Q6600 build. Monitor: a CRT of some kind, as always. (a 19” Dell currently.)

Some pictures/screenshots of the hardware...

Side (and lack of sidepanel )

Specs from CPU-Z and GPU-Z:

Of course, this wouldn’t be a momaka build without any ghetto repairs, right?
I’m sure many have already noticed the loosely “installed” side 120 mm fan and un-mounted HDD. But those are not the only thing. The main issue with that PC was with the rear expansion card bracket, which I fixed in the following manner:

I’m not exactly sure what happened to the case, but when I picked it up from the repair shop, the expansion card rear bracket area was all mangled and chewed up. Even the I/O shield on the motherboard was damaged. The simplest and cheapest solution/fix was to cut and grind all of the damaged metalwork with my angle-grinder and rotary cutter. After this, the case had no bracket for the expansion cards, so I made my own from an aluminum L-channel piece. This was much needed in order to have a discrete GPU card in the system.

It’s a ghetto fix sure, but it works well enough.

I’ve had this PC running since the end of last summer… or almost a year now. It’s had zero issues since then, so I’m not sure why that shop was getting rid of it. Probably the damaged case, if I had to guess. Also, in the winter, I temporarily switched the GPU to a Sapphire HD5830 1GB DDR5 to test it out, and because it was a GPU with higher TDP (good for making my room a little warmer/cozier in the winter months ). But with warm summer weather approaching again, it’s back to the HD6850. PC has no problems staying cool in 27C / 81F room temperature, which is the norm here for early summer. I suppose we will have to see how it does later in the summer when temperatures approach 30C / 86F __inside__. In any case, I really like the Optiplex 790 MT PC. It may look boring and unassuming much like all my other Dell PCs, but I think it’s another reliable workhorse and will likely remain my gaming PC for the summer and maybe up until it gets cold in the winter (at that point, I have a better but more hungry rig... that also needs postin' here. )
Attached Images
File Type: jpg Dell OptiPlex 790 PC (1).jpg (98.5 KB, 222 views)
File Type: jpg Dell OptiPlex 790 PC (2).jpg (261.6 KB, 218 views)
File Type: png Intel i5-2500 - CPU-Z.png (28.1 KB, 224 views)
File Type: png Dell Optiplex 790 motherboard - CPU-Z.png (19.1 KB, 226 views)
File Type: png Dell Optiplex 790 memory - CPU-Z.png (21.2 KB, 226 views)
File Type: jpg OptiPlex 790 rear - modded (1).jpg (109.0 KB, 226 views)
File Type: jpg Dell OptiPlex 790 PC (3).jpg (60.3 KB, 223 views)
File Type: png Samsung 8G PC3-12800 [M378b1g73eb0-yk0] - CPU-Z.png (20.8 KB, 225 views)

Last edited by momaka; 06-25-2020 at 04:36 PM..
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