Trixie5 :
Hey i'm looking to build a PC with either a Intel i7-2600k (Or 2500k if their is no substantial diff) or a AMD Phenome 1100T BE. What CPU could use all 16 gigs of ram before maxing out? Right now I have an Intel Core 2 duo with 2 gigs of ram (from 2007) and its Ram Max's before the CPU does. So I was looking to expand to 16 gigs. TRUST ME I will need it, I plan on running about 30 applications at once each one using 500MB. So is their any clear answer?
Both the Phenom II X6 1100T and the i5-2500/i7-2600 have two-channel unbuffered DDR3 memory controllers. You can have up to two modules of unbuffered RAM per channel and DDR3 can be made in up to 8 GB modules, giving each system the ability to use up to 32 GB of RAM. Your Core 2 Duo from 2007 likely uses two channels of unbuffered DDR2 memory, which comes in up to 4 GB modules, giving you a capacity of up to 16 GB on the board.
The way to increase the amount of memory supported by a CPU is to increase the number of memory channels, increase the number of modules you can put on each channel, or increase the size of the memory modules.
- Motherboards that support more than two memory channels tend to be server boards or server-derived boards. LGA1366 Core i7s have three-channel unbuffered DDR3 memory controllers, good for six modules per board (48 GB in total.) AMD's Socket G34 has four DDR3 memory channels per socket, which lets you use eight unbuffered DDR3 DIMMs (64 GB) per socket. Server boards also can have more than one socket, which gives you more memory channels. A dual Xeon 5500/5600 LGA1366 setup has six channels in total; a dual AMD G34 setup has 8 channels, and a quad G34 setup has 16 channels.
- Increasing the number of modules per channel requires registered memory. Registered DDR3 allows for up to 3 modules per channel compared to two per channel for unbuffered. Registered memory is only supported in server systems.
- Increasing the size of the modules requires either a newer memory spec or registered memory. DDR4 isn't out yet, but you can get 16 GB registered DDR3 modules, since the signal buffering in registered memory lets makers put more memory chips (36) on a single DIMM compared to unbuffered memory (16/18).
If you want to have a good amount of RAM relatively inexpensively, look for a dual-socket G34 (Opteron 6100/6200) setup. That lets you use up to 64 GB of inexpensive 4 GB unbuffered DDR3 DIMMs and up to 384 GB if you use expensive 16 GB registered DIMMs.