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Dell Optiplex 990 DT – Gaming Upgrade

Submitted by on December 13, 2015 – 12:05 pm 18 Comments
Dell Optiplex 990DT stripped

Just the way I found it
click for larger pic

Dell Optiplex 990 DT

Passing by an office building I noticed what looked like a newer model Dell Optiplex 990 DT gutted and set out for the cleaning crew to pick up for trash. This one caught my eye because it looked like everything except for the motherboard and processor had been removed. The wires were all pulled loose and the side panel was no where to be found. I assumed the motherboard and processor were bad but threw it in the back of my SUV where it eventually found itself sitting in my garage. Fast forward six months and needing another machine I remembered this one.



Referencing the Dell Service Tag C82F4V1 l I found that it was a Dell Optiplex 990 DT with a Core i5 2400 running at 3.10 GHZ. I thought there was no way anyone would have stripped it out and left a perfectly good Intel Core i5 2400 in the motherboard. I slapped in a power supply and a couple of sticks of ram, put all the wires back and was thoroughly shocked when it came right up to the bios screen. Being a long time gaming pc and case modder I had a ton of spare parts and decided to put this box back into action. This is what I came up with;

Dell Optiplex 990 upgrade parts

Parts for Upgrade
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Corsair CX430M Power Supply

This power supply is a perfect replacement for the original loud p.o.s. Dell Optiplex OEM power supply which is rated at only 230W. The OEM power supply barely supports the machine, forget any upgrading. The CX430M fits perfectly even fitting right into the locking mechanism for the case. It’s also 430W Bronze Rated, modular and has a 6 pin PCI Express power connector that the original did not. It’s also very quiet and looks great in the case. A definite upgrade for sure and 100% perfect replacement.



Gigabyte Windforce HD7850 Graphics 

The AMD HD7850 is the exact same card as the newer AMD R9 270 series. AMD simply re-badged the HD7850 using the same gpu and hardware with a new bios update only. Like the R9 270, the HD7850 can run Direct X12 and the new AMD Crimson Drivers. It’s also a very good graphics card that can easily run full HD at 30-45 fps in a lot of games and sometimes 60 fps. It will easily run 120 fps in Minecraft on max settings.  While it does use a 6 pin PCI Express power connector, it is a low power card maxing out at 125W under full load. This Windforce model is also very quiet. In any case it is a definite upgrade over the original lame Intel 2000 Graphics.

Dell Optiplex 990 Disassembled

Dell Optiplex Disassemled
click for larger pic

Corair Vengeance DDR3 CMZ8GX3M2A 1600OC

I have had two 8GB kits new in the package for over a year now. This is an extreme over kill since this machine has no OC abilities and runs at 1333 MHZ and is PC3-10600 compliant. The red anodized aluminum heat sinks on the ram looks great. This machine maxs out at 16GB which is more than enough for anything bar video editing. Corsair Vengeance is excellent memory. Just a side note, there is no difference between the colors, it’s just cosmetic if they are the same specs.

Seagate Laptop SSHD Hybrid 1000 TB

Like the memory I have had this just laying around new in a bulk packaging. This is kind of an odd choice for a mini tower but with the NAND memory and Seagate AMT Technology booting becomes much faster and frequenting used programs are “learned” by the Seagate Adaptive Memory Technology. This means as you use certain programs or applications, the drive learns and stores them in flash for next time use. In any case this drive is 5X faster than original 7200 250GB it came with not to mention a whole lot quieter. There is no audible sound detectable even on prolonged reads.

Corsair H80iGT High Performance Liquid Water Cooler 

I’ve just been looking for a reason to use this awesome cooler. Without a doubt this is well beyond any cooling needs as the Intel i5 2400 is core locked and runs extremely cool using the stock fan. I just thought it would be totally extreme to throw this in the system and would look great. I can always put this any of this hardware in another system if I want.

Other Components

  • Asus PCE-N53 Dual Band Wireless N600 PCIE 1X Adappter
  • Antec Arctic 7 Nano Diamond Thermal Paste
  • Corsair AF120 Red Led Fan
  • Red Led Strip
  • Standard DVD+ Writer
  • Red anodized thumb screws
  • Ultraviolet reactive tie wraps


Assembly and Conclusion

Dell Optiplex 990 Gaming Upgrade

click for larger pic

Putting it altogether was pretty straight forward. I disassembled the case and cleaned it out thoroughly. I also had to remove the OEM hard drive cage to make room for the 120mm radiator and fan for the H80iGT. As you can see it looks sharp and performs flawlessly.

The original Windows 7 Pro COA activated with no problem and the free Windows 10 Pro upgrade went without any issue whatsoever. I also updated the bios to the latest Dell version. Combining Windows 10 Pro with the Seagate SSHD results in boot times under 10 seconds with most programs including Chrome, Firefox and IE10 opening almost instantaneous.

This machine was purpose built for Minecraft and Need For Speed. In Minecraft and NFS it runs max settings at 120 FPS without hesitation. PC Mark 8 scores 3319 on the Creative Benchmark which is a 4 hour test and on the PC Mark 8 Home Test scored 4117 which was 74% better than all results reported for an Intel i5-2400. To test the cooling of the H80 iGT i ran it on Prime 95 max burn in for 24 hours straight. Using Real Temp to record the results it never crossed 37 C which is outright freezing in CPU terms while running on Quiet Mode only on the H80iGT. All in all I am very satisfied with this machine and so is my 8 year old Minecraft warrior!



Check out the video below of this upgrade.


  • Roberto says:

    Hi, im building my first pc and was wondering if it was difficult for you to remove the hard drive cage? I recently bought this computer and an msi gtx 960oc, and its too long.

  • Stangalang says:

    Make sure you have 90 degree angle SATA cables as they also might get in the way of your video card.

  • Stangalang says:

    Awesome build. I’ve always loved taking Dells and making them gaming machines. I took an i7 Optiplex 990 and added a 500W PSU, GTX 950, 16GB RAm and 2x SSD’s to make it my wife’s gaming rig

  • kev says:

    Now we need someone to figure out how to upgrade to a new case. Mainly pinouts for power switch and front panel

  • Jay says:

    I wanted to share my optiplex 990 story.

    I came across a Dell optiplex 990 with the i5-2500k for $80 … anyway, i watched this video and immediately started buying my parts. My first purchase was the RAM ( which in this case anything was better than what it came with) I spent $35 on 8gb crucial ballistix sport.

    Next I got a EVGA gtx 660 SC for $70 (used) and this is when I ran into my first problem. I needed a better power supply! Let it be known this case will only take 5.5 inches (long ways) on the power supply. Either get the corsair on the video or an EVGA 500W bronze or similar.

    Another problem with adding a larger GPU is that they can get in the way of other things. In the instance of my GTX 660, the damn thing wouldn’t snap into place due to the SATA cables. You may need to purchase 90 degree cables and even better if they have the wires coming out the long way. With the regular 90 degree cables you can only use one at the end… also I needed a few more millimeters just surfaced the cable heads a little and the plastic case of the GTX 660. (I only recommend this if you know what you’re doing)

    My next project is to add an SSD and possibly the water cooling. Just wanted to say this video inspired me to create something out of my $80 optiplex 990.

  • Jeremy says:

    I just bought a Dell Optiplex 990 and it came with a 2 TB Drive 16 Gbytes of memory and alas, no wireless and no HDMI. I game using a 42″ TV. I have an open PCI bus but I do not see any cards that do HDMI for this. Can anyone help me?

  • frumence says:

    is it possible to move a small factor optiplex 990 into a different case from corshair or fractal design?

  • Anonymous says:

    i would also like to know how you removed the HDD cage i like how you replaced it with a fan brilliant!

  • BobbyLaGrosse says:

    Awesome build 😉 I’d like to swap my 990SFF one for a minitour 990 to make an atomic hackintosh ! beacause i can’t use the actual mobo into an atx case beacause of the socket and the fan cooler (proprietary format i think…) and too enough work to adapt the TPM and connector to buttons and front USB and audio…..

  • Nuclear Mike Roberson says:

    Is this a MT? If so, what are in your card slots?

  • Andy says:

    Hey there Danny,

    I recently bought a Optiplex 990 off local classified ads (local guy buys auction lots of office PCs) and I replaced the PSU with Antec 430 (quite the coincidence) and inserted my 7790 that I’ve used for the last few years.

    For some reason I’m getting stuttering in rocket league, which is driving me crazy. Do you have any suggestions as to what could be causing this?

    I’ve read some horror stories about the PCIE slot not supporting the wattage the card needs, but given that you’re using a 7850 with the exact same PSU I find it unlikely to be a power issue.

    I’ll be running Heaven and Valley benchmarks tonight to see if I can replicate the issue there.

    Please let me know any ideas you might have!



  • Eli says:

    I need help. I picked up a dell 990 like you did. Someone left it. So I put in my power supply and video card from my older tower into the 990. I also bought 8 gigs of ram. I installed the drivers but when playing games it runs very sloppy. I have tried running the forest on medium graphics but it runs horrible. My older duo core tower was able to handle the game perfectly fine. I can’t figure out what is wrong. Any suggestions?

  • Alec says:

    Get a new hard drive

  • khubaib Farooq says:

    Dear , How did you removed the HDD cage ?

  • Jim Galloway says:

    For anyone wondering who may have stumbled across this thread from Google, this is how I removed the hard drive cage on my OptiPlex 9010 which should be the same as the 990:

    – Remove everything from the case…power supply, motherboard, drive, etc. There will be metal shavings to clean up and you don’t want them in your components.
    – Take off the front bezel of the case to prevent damage to it.
    – Turn over the case and locate the 5 rivets that connect to the bottom of the hard drive cage.
    – Use a small nail to hammer out the center of each rivet until you hear it pop out into the case. It will be a small piece of metal and allow for the rest of the rivet to easily be removed. I used a hammer because drilling makes a huge mess inside the case.
    – Turn the case back up and use a tool that’s metal, thin, and sturdy to hammer away the rest of the rivets by lining up the edge of the tool with the edge of the rivet. I ended up using a painter’s 5-in-1 tool which was perfect for most of the work although I’m sure there are much better options out there.
    – Now look at the front of the hard drive cage and notice how the right side of it is attached to the front of the case. There are two brackets connected at the top and three connections at the bottom. Carefully line up whatever tool you use between each point and hammer through. Just be careful on the bottom 3 not to damage the rivets holding the front of the case together.
    – Now the most frustrating part, the back of the hard drive cage is attached to the side of the case with something similar to rivets but you can’t see them until you pull the cage left and right. Starting on the left side on the back of the hard drive cage, position your tool behind the hard drive cage and near the middle…try to hammer through.
    – Once the left side is free, pull up on the cage and do the same to the right side and you will finally be free!
    – Clean up any rivets and metal shavings.

    This was my “just smash” approach, I’m sure there are smoother ways of handling this. Hopefully this helps someone.

  • Julian says:

    These Dell 990’s are easy to get and great for a cheap gaming. If you can find an i5 or i7 they are a brilliant base machine. You don’t need to remove the HD cage for a big graphics card as there is lots of room in the case. I have a EVGA GeForce GTX 970 4G with twin fans and it’s fine in there. 600w PS, 2 x SSD and 16gb Ram. I’m running HD games at 70fps.

  • Liam says:

    Are you running games is the max setting and is the GTX 970 the best card it can have. Have you tried to play overwatch? Is it 1080p?

  • Anonymous says:

    Julian, whats the model and brand your running for that 600w PS?

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