How Much DDR3 memory do I really Need?

[stuperprohero]

I built my 1st gaming PC 7 years ago. It's been awesome and reliable but now it's outdated. I want to play Crysis, COD4 and other high end games on high(preferably highest) settings at 1024X768.

I've been reading tons lately about all the new stuff out. The thing I'm stuck on is how much DDR3 RAM do I really need to run the best games smoothly?
I know I am going with an ATI 5870 GPUNewegg.com - ASUS EAH5870/2DIS/1GD5/A Radeon HD 5870 (Cypress XT) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card w/ATI Eyefinity - Desktop Graphics / Video Cards

I am stuck between getting an Intel i7 2.66 Newegg.com - Intel Core i7-920 Bloomfield 2.66GHz 4 x 256KB L2 Cache 8MB L3 Cache LGA 1366 130W Quad-Core Processor - Processors - Desktops

Or AMD Phenom II X4 965 Black Edition Deneb 3.4GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Newegg.com - AMD Phenom II X4 965 Black Edition Deneb 3.4GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Processor - Processors - Desktops

The issue I'm having is the mobo I'm considering for the i7 has 6 DDR3 slots and supports up to 24Gb of memory and is triple channel. Newegg.com - ASUS Rampage II Extreme LGA 1366 Intel X58 ATX Intel Motherboard - Intel Motherboards

The AMD mobo's have 4 memory slots, supports up to 16Gb ram and is only dual channel.

How much memory do I need to run all the great games as stated in my first sentence? Is there a huge difference between double or triple channel? I was considering 12Gb of DDR3 memory but if I don't need that much I could save money by going with less or even going AMD on the CPU.

With the i7 rig and 12Gb of memory I'm looking at $1600-$1700, I prefer to keep costs down.

 

[S0ULphIRE]

The usual amount gamers usually go for is about 6Gb (3x2Gb sticks)
That will handle whatever game you throw at it no probs.

The only people who need more ram are the graphic designers and video editors. Then 12Gb might be needed, but for just gaming 6Gb is more than enough.

 

[Fat.Clown]

for games specifically, no gains above 4 gb really

Benchmark Results: 3D Games - Review Tom's Hardware : Do You Really Need More Than 6 GB Of RAM?

 

[Hefemeister]

PII = 4gb

i7 920 = 6gb due to triple channel mode.

 

[stuperprohero]

Thanks everyone.
So which CPU would you recommend between the two? Or something else?

Thanks for the link Fat Clown, that was some good reading.

 

[Fat.Clown]

Thanks everyone.
So which CPU would you recommend between the two? Or something else?

so what's your budget?

 

[stuperprohero]

My budget allows about $1600-$1700 but I'd rather not spend $500-$600 on a CPU. Only needing 4-5 Gb of Ram is a huge savings already. I thought if the i7 was overkill I could go AMD. I'd rather have the i7 if it's that much better but not if it's overkill..

My old rig is an ASUS P4PE mobo
1 Gig of Ram
Intel Pentium4 2.8 ghz
ATI XT1650 series which is standard PCI
Maxtor 6L300RO hard drive
Thermaltake Case

I have to play COD4 on the lowest settings and it still stutters sometimes.
Also if it makes a difference I will be using this PC as a home theater so I will need slots for a tuner card.

 

[Hefemeister]

for pure gaming the i7 is a bit overkill but your budget allows for it. It is nice to have but a PII/i5 are great for gaming and will save you a few hundred bucks.

Do you need a monitor in your budget?

 

[stuperprohero]

Yes I could use a monitor but I can pick a cheap one up used.. Right now I have a CMV CT-934-D 19" LCD?
the thing is I need a computer at work so I thought I would us this one at work since it's out dated and I would build a new one for home/gaming/home theater.

 

[Hefemeister]

With the gpu you have selected a monitor with resolution less than 1920x1080 would be a waste. I do not have the time right now but with your budget we should be able to put that all together for you.