Upgrading soon. CPU, Motherboard, RAM question/help

[xEcliptic93]

Hello. I'm having THE worst time with CPU's, Motherboards, and RAM.

First of all: I'm on a budget of a max of $600. I can try to go to $700 if needed but try to stay with $600.

I'm going to be upgrading my 2 year old PC very soon and need some help picking out a reliable CPU and Motherboard. I always see a lot of mixed reviews on Motherboards I have looked at on Newegg and I figured I'd rather ask people with a brain over here on Tom's Hardware for some suggestions. Once this upgrade is complete the PC will be used for playing Battlefield 3 and Star Wars: The Old Republic mainly. I don't HAVE to max out Battlefield 3 or anything. Just looking for a nice playable quality (medium/high).

My current setup:
CPU: Intel Core 2 Duo E8400 running @ 3.00 GHz
CPU Cooler: Arctic Cooling Freezer Pro 7 Rev. 1
Motherboard: Gigabyte GA-EP45-UD3P
RAM: G.Skill 4GB (2x2) DDR2 800
Graphics Card: ATI Radeon HD 4850 running with DirectX11
PSU: Corsair VX550W
Case: Lancool Dragonlord PC-K92
Resolution: 1440x900
Operating System: Windows 7 Home Premium 64bit

Parts being upgraded/what I'm upgrading to:
CPU: Need help
CPU Cooling: I plan on buying the Arctic Cooling Freezer Pro 7 Rev. 2 ($33) because the Rev. 1 has done wonders for temps
Motherboard: Need help
RAM: Need help (having trouble picking between 1333 and 1600)
Graphics Card: Most likely a Sapphire Radeon HD 6870 1GB ($180). Wanted to get a Nvidia 560 ti but I'm on a budget and I've had good experiences with ATI, hence my current card.
Operating System: Windows 7 Home Premium 64bit ($100)

Total so far with shipping: $312.96
^This total is part of my UPGRADE BUDGET of $600 - $700

I'm looking for some suggestions for a GOOD and RELIABLE CPU, Motherboard, and RAM. Especially the Motherboard because the Gigabyte one I have currently has been GREAT but sadly it's very out of date for the newer CPU's that don't have a 775 socket like this one has. I'm on a budget of a max of $600 like stated above also. Also looking for thoughts on my upgrade, I feel it will do the job. If you need any more information, just ask.

Thank you.

 

[xEcliptic93]

1. Budget is $600 - $700 with the $313 already there. Probably should have added that, sorry. The $313 is just the total from that budget I have so far. My component upgrade budget is $600 - $700.

2. No, love my monitor until it literally explodes haha

EDIT: Still doing research on MB's and CPU's myself. Came across these:

CPU: Intel Core i5-2400 Sandy Bridge 3.1GHz (3.4GHz Turbo Boost) LGA 1155. Quad Core.
Motherboard: ASRock P67 EXTREME4 GEN3 PCI-e 3.0 may be good to have later on down the line. Probably not this board though, I don't think the Radeon HD 6870 will even fit... So still looking.

 

[xEcliptic93]

Hmm. That actually helps a bit. I wasn't sure how the 6870 would fair with my resolution. I'm don't really know how Video Cards and Monitors work together. Personally, I don't really want to get rid of this monitor just yet. May move up to an 2500k and move the video card down to a 6850.

Running at 1440x900 how should I go about video cards? I mean eventually some time down the line I will upgrade my monitor but not yet. Just need some more explaining on this overkill for the video card and resolution.

 

[xEcliptic93]

Thank you for this help on my parts and explaining the Monitor to Video Card thing! Makes a lot more sense now

 

[xEcliptic93]

Question:

The ATI Radeon HD 6850 card is PCIe 2.1 and my Motherboard is 2x PCIe 3.0 (16x and 8x), will the card work in a PCIe 3.0 slot? I mean it fits but will it run?

 

[xEcliptic93]

Best answer selected by xEcliptic93.

 

[xEcliptic93]

Thank you!