OptiPlex 7020 MT Video/Power Upgrades

Question

I recently acquired a Dell OptiPlex 7020 MT through work for a good price and the option to use payroll deduction to spread out the cost. Let me start by saying that I realize this is really meant for the office and not for home/gaming purposes. However, having the i7, 16 GB of RAM, etc. makes it tempting just to do a little bit of gaming at home. However, I've been rather underwhelmed by the AMD R5 240's performance.
I've been looking at what my options are for upgrading, and I'm left with a couple of questions.
- The NVIDIA GeForce GTX 750 Ti seems like a good card to go for. Not too expensive at $100-150 and there's low power consumption at around 55-60 watts (up from the 50 watts that the R5 240 supposedly uses). However, most pages I can find for this card recommend a minimum of a 300 watt power supply, while the 7020 comes with a 290 watt (80 plus bronze) power supply. It seems like it would be pushing it to try to make it work anyways. On the other hand, it doesn't seem like much more power usage than the current video card. There's the argument that I'll never hit 100% power utilization on all of the components in the system (and you'd hope that there would be extra power capacity for an additional hard drive, etc.), but I don't like taking that gamble. There's also the issue of BIOS compatibility, etc. that I've heard others complain about with third-party video cards. Has anyone had success with a GTX 750 Ti or even just the plain GTX 750 with 2 GBs of RAM in an OptiPlex 7020 MT with the stock power supply?
- The next upgrade to look into logically is the power supply. Dell chooses this exact same video card, the GTX 750 Ti, for the higher end of their XPS line of desktops, though they are nice enough to include a 460 watt power supply for that configuration. I know previous models of the OptiPlex and Precision machines that I've worked with have been using standard ATX connections for a while now. Suffice it to say that I am VERY disappointed that Dell has gone to using a proprietary 8-pin connector from the power supply on the 7020, reminding me of older models that used to try the same thing. I checked and even our 7010's have the regular ATX power connections. So disappointed! This will likely be the last Dell I buy for awhile if they keep that kind of stuff up. Nevertheless, I'm pretty much stuck with this purchase until I pay it off, so I'd like to figure some kind of solution out. Are there any options for upgrading the power supply in the OptiPlex 7020 MT, even if it means changing pins in the connectors or getting a higher capacity power supply from a different Dell model that uses the same connection with the motherboard?
Again, I realize this is meant to be an office machine and not a home/gaming machine. I'm trying to make it something it isn't really intended to do. I also realize this is a fairly new model, hence the lack of good information out there for what people have and haven't tried with it yet. Any helpful information would be greatly appreciated! I also hope this helps prevent anyone else from making the mistake I did by thinking they could buy this machine and easily upgrade the video card/power supply afterwards. Finally, please let me know if additional information is needed.
Travis

Answer 1

Newer Dells even with 305W power supplies have 20 to 25W on the +5VSB.
This means you must use an EPS 12V 2.92 certified supply because ATX even version 2.4 only requires 10W on the +5VSB
Minimum Recommended Upgrade for A Dell Tower is CORSAIR CS750M.
550W is too small.  Generic 550W power supplys are NOT AS GOOD as the Dell 305W power supply.
The EPS12V spec 2.92 guarantees 170w combined on the 5V/3.3V rails and 20W on the 5VSB as well as 45 amps on a Single 12V rail.
Note on the Label for the Dell that they provide 20W on the 5VSB.
If you add up all the currents its more than 305W but Dell does not overstate the total output of the supply.
5V @ 22A = 110W
5VSB @ 4A = 20W
3.3V @ 17A = 56.1 W
12V @ 36A = 432 W
-12 @ 1A = 12W
630.1 W Total on 305W power supply.
80 percent of 750 = 600W
80 percent of 550 = 440W
This means that 550W supplies for some dell models will not even turn on the machine due to lack of power in specific areas.
And no supply is 100 percent efficient.
This is why I recommend an EPS12v  Corsair CS750M
DELL's 525W power supply Guarantees 150W on the 3.3v and 5v Rails. But also again Rates the 5VSB at 20W.
You Need an EPS12V 2.92 certified Power Supply
Dell supply's have 20 to 25W on +5VSB and most cheapo units have 10W or less.   Dell Supply's guaranteed 130 to 180W on 3.3v/5v rail and Others do not.
Minimum recommended unit is CORSAIR CS750M.
http://www.microcenter.com/product/425477/CS_Series_CS750M_750_Watt_ATX_Modular_Power_Supply
http://www.amazon.com/Corsair-Series-Modular-Efficient-CS750M/dp/B00GH9NA0A
http://www.corsair.com/en-us/cs-series-modular-cs750m-750-watt-80-plus-gold-certified-psu
Corsair CS Series 750 Watt ATX Modular and Efficient Power Supply CS750M is a suitable brand I find on Amazon and in Microcenter.
Corsair CS750M EPS12V 2.92
DC Output Rating
DC Output
+3.3V
+5V
+12V
-12V
+5Vsb
Max Load
25A
25A
62A
0.8A
3.0A
Maximum
130W
744W
9.6W
15W
Total Power: 750W