Upgrade old C2D PC w/ $400?

[jzsang]

Hello,

I have an "old" computer that I'd like to upgrade. Its specs are as follows

CPU: E8400
Mobo: GA-EP35-DS3L
RAM: 4 GB DDR2 800 mhz
GPU: HD 5850
HDD: 750 GB
OS: Windows Vista (ugh)
PSU: 610 watts, NOT modular
DVD drive: Standard issue DVD drive, NOT slim
Case: Antec 900
Monitor / TV resolution: 1920 x 1080

(Q) Anyways, if you were willing to spend up $400 and were interested in gaming and / or possibly turning this into a HTPC, what would you do?

Additional notes:

(1) I expect to upgrade my CPU and motherboard
(2) I'm thinking I should upgrade my RAM, HDD, and OS
(3) I don't expect to upgrade my GPU and PSU
(4) I'm tempted to upgrade the case to something much smaller, but want to be able to use my HD 5850
(5) I prefer not to overclock

Thank you in advance,

 

[e_X]

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i3-3220 3.3GHz Dual-Core Processor ($129.99 @ Newegg)
Motherboard: ASRock Z77 Pro3 ATX LGA1155 Motherboard ($87.55 @ Newegg)
Memory: Wintec One 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($69.99 @ NCIX US)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.98 @ Outlet PC)
Total: $400.50
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-01-23 22:37 EST-0500)

 

[AMD Radeon]

your mobo is ATX, so buying mATX case is impossible, for upgrade : i believe you dont want to spend 400 to something similar performance...

wait for june and save your money until new intel cpu comes up

 

[ikes9711]

Also your HDD is fine there is really need unless you are doing some serious video editing or for some odd reason have managed to fill up 750Gb with other data