Computer gurus - RAM architecture question

[Brad Johnson]

The machine I have coming has 2 GB installed that fills two of the four total slots. The machine takes PC2 6400 SDRAM.

It's set up for dual channel and I know it works best if RAM is added in matched pairs. Question is, should I wait to see what version the installed sticks are and try to match the second pair to the first, or not worry about it and just get two more decent-quality sticks on the way?

Also, in perusing available RAM over on NewEgg, there are only about a zillion choices in PC2 6400-compatible RAM. Any particular features I need to watch for in order to maximize performance, or will any PC26400-compatible sticks work?

Also, if I decide to bite the bullet and get a 2-stick 4GB kit, is it better to install the larger sticks in the first two slots, or does it matter?

Brad

[Gewehr98]

Dunno.

You selling your old RDRAM?  (I have 5 machines here that still use the stuff...)   

[Brad Johnson]

The old machine has 768 MB in it (two 256's and two 128's). I'll be keeping it functional for a while, just in case I find some data that didn't make it across properly. After that, who knows?

Brad

[Hawkmoon]

What operating system? Wondows Xp doesn't need (and can't use, so I've been told by IT professionals) more than 2GB of RAM, so if this new machine will be running Xp ... save your pennies.

[Cromlech]

Wondows Xp doesn't need (and can't use, so I've been told by IT professionals) more than 2GB of RAM

I assume that they mean it won't use up more than 2GB, as my XP Rig is sitting pretty with 6GB DDR3 (Core i7 Asus P6T6 WS Revolution). Though I am on XP x64 Pro.

[RocketMan]

What operating system? Wondows Xp doesn't need (and can't use, so I've been told by IT professionals) more than 2GB of RAM, so if this new machine will be running Xp ... save your pennies.

True, except the numbers are closer to 3.2GB for XP Home and almost 4GB for XP Pro.  XP 64 bit has no practical limit under normal use, given that it is 128GB.

[Azrael256]

The answers depend heavily on the memory controller on the board.  Some boards can handle wacky combinations of memory by disabling interleaving, downclocking, etc.  You'll even find boards that can handle dual channel in this pair, and a single channel in one of the other slots.  You can easily have a sub-optimal configuration work just fine.

Your safest bet is to make sure it's all identical.  Failing that, match type (PC6400 single or dual), and match CAS Latency (CL8.5 or whatever).  Usually you'll put the biggest sticks in the first slots and go down from there.  The idea was that you'd want to fill one stick as much as possible before opening the other channel.  Since Windows is really using all of the memory (almost) all of the time, that may not be true anymore.  Consult the manual on that.

I would wait, since you don't really know which sticks you have.  You can google the part numbers on the DRAM chips to find out exactly what they are if the documentation doesn't say.

[KPT]

Can I ask why you want more than two gigs on a machine that is replacing a ME machine??

If it was me I'd not use the two gigs the machine came with and get 2x2 gigs. That is what I did when I upgraded the ram in my server.

Unlike previous MS os's, 7 seems to be good at memory management.

The server with 4 gigs (don't think its idle from CPU usage, look at processes):



And the laptop with 2 gigs (both are 7 7600 64 bit):

[Brad Johnson]

Can I ask why you want more than two gigs on a machine that is replacing a ME machine??

RAM is cheap performance.  At the minimal price for an added 4GB I'd rather have it and not need it than need it and not have it.  It may be needed only once in a blue moon, but, like insurance, when you need it you really need it.

As I said in my original post the 2GB set in the machine will stay. I'm getting a 4GB set (2x2GB) that will fill the other two slots for a total of 6GB.  Why?  Because it's cheap, easy, and I've been working with computers long enough to know that today's Overkill is tomorrow's Not Enough.

Brad

[mellestad]

Short answer:  It won't make enough difference to worry about.

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231098  <-- Decent brand, decent price, good warranty.  It will be at least as good as whatever comes in the machine.

(or this if you want 4GB more http://www.newegg.com/Product/Product.aspx?Item=N82E16820145184)

[Thylacine]

As I said in my original post the 2GB set in the machine will stay.

If your old memory is slower than your new memory, you will be slowing the new memory.  I always use the fastest memory supported by the system.

 

[Gewehr98]

That doesn't reveal the entire story.

4Gb offers extra headroom for applications that require/hog it. With 32-Bit XP, you're only accessing about 3.5Gb, but that's still a reserve of extra performance above 1Gb or 2Gb.  Start running something intensive on a machine with 1Gb, and watch the hard drive thrash to keep up.

I can have eleventy-billion threads running in the background on my quad-CPU workstation here, and it'll barely bump the graph above zero - it just depends on how that code allocates or uses the memory.

[Brad Johnson]

Wow, I ran into a special on Corsair RAM over at Tiger Direct. PC2-6400 4GB kits for $50 each. Part of it is a mail-in rebate, but I can handle that. Total price $102 for 8 gigs. Not bad considering I the 4GB kits normally run around $75.

Overkill? Sure, for now. But one of these days it won't be.

Brad

[Perd Hapley]

When reading the above statement, keep in mind the subject has a history of using one computer system for geological ages.  He will need his 8 G's thirty years from now, when holographic emails become standard. 

[Brad Johnson]

Fancypants new fangled technology. Bah!

Brad

[tyme]

8gb is good.  Like Gewehr said, make sure you're using 64-bit windows or you just wasted $50.

[Brad Johnson]

8gb is good.  Like Gewehr said, make sure you're using 64-bit windows or you just wasted $50.

Win 7 Home Premium 64-bit.  The new machine qualifed for the free upgrade. 

The RAM is already installed and the machine, which is currently boxed and awaiting arrival of the Win 7 upgrade disk.  I'm not even going to boot it until I can do it with the upgrade disk in the drive.

Brad