How much Fps will improve if i....

Your FPS will at least double with the new card. Obviously the 7850 is more than 2x as powerful as the 5450 (like 20x more powerful) but Sleeping Dogs is very CPU intensive. But it will be fully CPU bottlenecked at the settings you're playing at now, and you'll be able to crank it up to ultra, no problem, and get decent FPS.

This one looks cheap, cool, and quiet:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102998

What PSU you have? Danny - what is that?

crisan_tiberiu said:
Also, i recommend you OC your CPU to atleast 3 GHz, or 3.2 GHz so you wont bottleneck your GPU that much

Click to expand...

You can not overclock this Dell.

Now about GPU.


I think I have to step in since not so many users know the limitations of Optiplex Mini Tower cases - this is not your typical small ATX case, it is BTX case, and not all video cards can fit, so I will provide you all with small guide into Optiplex MT GPU upgrading.

THIS POST APPLICABLE TO MT (MINI TOWER) FORM FACTOR ONLY.

Unfortunately no card that is more than 7.5 inches long or 2 slots wide will PHYSICALLY FIT inside the case - it was found that only single bracket video card can fit due to BTX MOBO, where card internals facing upward towards PC internals, not ATX, where dual card design is blocking another PCI slot by facing downward.
If you prefer the card with beefier fan, then the length of the card must not exceed 7.5 inches, otherwise only "skinny" single bracket, single slot cards can physically fit.

Pictures below will prove my point.

View shows no room for dual bracket



Single bracket only, or you have to cut dual bracket in half



This is the other way to show my point



Here you can clearly see only single place for the bracket



Visual explanation



7.5 inches explained, also shown "obstacles"



This is the picture of actual "skinny" single slot video card (not sure which model)- perfect, "glove" fit.



There is additional problem, which I can not check - there are tall transistors on motherboard (this is Optiplex 745 Mini Tower motherboard)





take a close look at PCIE slot (the one to the right, with blue holder lever), next to the lever you can see 2 black tall transistors, this could be a problem for low sitting card, it was never reported to my knowledge on Optiplex 745 (similar problem was reported on Optiplex GX620, which has more transistors like this, so it could be not applicable here).


I will list below strongest and largest cards, which can fit, in addition to those, most low profile cards will fit as well, the best in this class is

SAPPHIRE 100357LP Radeon HD 7750 1GB 128-bit GDDR5 PCI Express 3.0 x16 HDCP Ready Low Profile Video Card http://www.newegg.com/Product/Product.aspx?Item=N82E16814202002

So, I found 2 GDDR5 7750 cards and one DDR3 4GB (GDDR5 is better than GDDR3, even if GDD3 offers 2 GB RAM or more), which confirmed in reviews to fit Optiplex gx620, 745 and 755 cases (the difference between those models are different processors).

Skinny, flimsier in terms of construction, completely single slot XFX 7750 http://www.amazon.com/XFX-DisplayPort-PCI-Express-FX775AZNP4-FX-775A-ZNP4/dp/B007Z3T5JC

A bit beefier cooler, not as skinny, more durable in construction PowerColor AX7750 http://www.amazon.com/PowerColor-AX7750-1GBD5-DH-Video-Graphics/dp/B00775OC28/ref=sr_1_1?ie=UTF8&qid=1362783129&sr=8-1&keywords=AX7750+1GBD5-DH

If you need Video card for working with high resolutions, BUT NOT FOR GAMING, PowerColor AX7750 4GBK3-H Radeon HD 7750 4GB is DDR3 card with huge 4GB memory, but is is not as fast as DDR5 and loosing in games http://www.newegg.com/Product/Product.aspx?Item=N82E16814131486&Tpk=7750&IsVirtualParent=1
Here is review of this card http://news.softpedia.com/news/PowerColor-Launches-Single-Slot-Radeon-HD-7750-4-GB-Video-Card-292712.shtml so this one is not for gamers!

I cannot say which one of those 2 DDR5 is better, both are good and got less bad reviews related to structural build.

Next will follow maximum possible upgrade, 7750 is weaker...

So far I found only 2 7770 video cards which will fit inside - PowerColor AX7770 http://www.newegg.com/Product/Product.aspx?Item=N82E16814131477

HIS H777FN1G Radeon HD 7770 very tight fit, almost touching heatsink http://www.newegg.com/Product/Product.aspx?Item=N82E16814161433

There are 3 GTX650 cards in North America, which most likely will fit (tall transistor is the only problem).

PNY VCGGTX650XPB GeForce GTX 650 2GB 128-bit GDDR5 http://www.newegg.com/Product/Product.aspx?Item=N82E16814133474

PNY VCGGTX6501XPB GeForce GTX 650 1GB 128-bit GDDR5
http://www.newegg.com/Product/Product.aspx?Item=N82E16814133471

ZOTAC ZT-61008-10M GeForce GTX 650 1GB 128-bit GDDR5
http://www.newegg.com/Product/Product.aspx?Item=N82E16814500290

PNY cards will require power supply upgrade. Zotac do not need power supply upgrade.

Following card is already out of production, so if you can find it on Craig list or eBay, it is only way, also I seen it on Amazon for a high price http://www.amazon.com/Sparkle-SX650TI1024KD-SPARKLESX650TI1024KD--Grafikkarten/dp/B009ZC3MHM/ref=sr_1_1?ie=UTF8&qid=1371676541&sr=8-1&keywords=SX650TI1024KD
From NVIDIA I see SPARKLE 700025 (SX650TI1024KD) GeForce GTX 650 Ti http://www.newegg.com/Product/Product.aspx?Item=N82E16814187200 this link provided for reference only

So, your maximum upgrade is GTX650 or HD7770, your choice.

Anything else I can help you with?