System RAM upgrade question.
 

OK Xmas money is being spend on RAM upgrade. My Mobo can handle 4 GB of RAM but XP Home will only see 3 possibly 3.5 so getting 4 is pointless so I will get 3.

Now I have 4 slots so I was thinking 2 slots will have matched 1 GB modules and the other slots will have 1 x 512MB Module each matched of course. Is this the way to go?

About whether Xp 32bit can see 3GB or 3.5GB which one is correct. Either way 3.5 would end up with one unmatched pair.

As far as I know, the problem is not that XP will not 'support' 4GB, as far as I'm aware, it actually will, it's just that it won't allocate more than 2GB to a single process, or at least that's the case with the 32Bit version, the 64Bit version is capable of doing so. Some older Asus motherboards can cause issues too apparently, with a bottleneck at one of the bridges. Even so, it is still worth getting 4GB of RAM, just don't expect 4GB of work on a single app.

:D Chock

Cheers chock

I know that Xp will find 3.5 of 4 and allocate the other half gig to OS or GFX card? Since my GFX card uses some system RAM this can only be good.

I'll get whole 4. A bit of reading cleared that one up.

It seems a good time to get memory too. I can't believe how cheap it now is. A year ago it cost me £200 for some top notch Corsair Dominator DDR2 matched 2GB pair. Now I can get better RAM that that for less than £100.00. :damn:

Hell yes. I just bought 2gb of low latency OCZ dual channel DDR2-800... $20 after mail-in rebate. NOW IS THE TIME!

3gb is pointless on xp and actually slower then just a pair of 1gig sticks.

stick a decent pair of ddr2 1 gig pc6400 sticks in the 1st and 3rd ram slots for dual channel and away you go. stick another stick in and it gets knocked back down to the slightly slower single channel and xp rarely pulls more then 2gigs even with a very hefty game going.

just a few results from my system

3dmark06-

e6600 @ 3.2ghz
8800 gts 320
2x1gb sticks single channel

13412 3dmarks

3x1gb sticks single channel

13416 3dmarks

2x1gb sticks dual channel

13700 3dmarks


nowadays the graphics card is much more important presuming you have a decent c2d cpu.

Yes, XP can address 3 GB for apps, and load the kernel into the 4th GB. So it can use 4 GB of RAM, but not all of it completely.

ANy app made with Visual Studio 6.0 or later can also address 3 GB, but only after you add the /3gb switch to your boot.ini. Without the /3gb swtich, your machine will act as only having 2 GB addressable. I've known many a person that put 4 GB in their system, yet complained it didn't work. Of course it won't work, unless you tell Windows to use it!!!

-S

PS. I forgot to mention that apps made prior to Visual Studio 6 (which came out in the late 1990's) may get completely borked by having 3 GB available. And not everyone was programming on Vis Studio 6 yet in 1999 by the way. So for these apps old old old apps, you may need to remove the /3gb switch and reboot your computer to play them. Just a warning.

Once in a while I thinik about getting one 1 GB bar to help my FS installation a bit, I now have 2 x 512 Mb bars installed in slot 1 and 3 (of four). Is there a problem in mixing RAM bars of different capacity? How to arrange 2x512MB and 1x1GB on the four slots? Or is it unimportant? two years ago i was told it is not unimportant at all, and best is to use only bars of the same capacity. but I do not wish to replace the 512-bars, i only want to add another 1 GB.

Most boards these days use what is known as crossbar technology which is more widely known as dual channel. Most boards I think can switch between dual channel and single channel fine. On the same channel, mixing RAM is fine, as long as the same RAM is on the opposite channel. This will allow for dual channel operation (4 transactions per clock cycle for DDR and 8 transactions per clock cycle for DDR2).

In my mind, dual channel won't really give you any speed improvements though, so don't fret too much about it. You still can't saturate normal DDR400 these days, let alone trying to saturate DDR 800.

The final word however is your manual. Each board is different on what RAM combinations they support and that will be listed in there. Also high density vs low density RAM can be an issue too (the number of chips on the module). That is something else to consider. Buy from a decent manufacturer like Mushkin, and you will be fine.

-S

Thanks. So while having 512 in slot #1 and #3, I can put in 1GB in #2 or #4? Or better another 2x512? - I (would) buy it exclusively to help FS9 to switch between different sights, panel views, outside views, which sometimes causes delays, especially when returning to virtual cockpit. I assume that RAM would help there since FS still is very CPU dependant, and does not allocate so much of the graphics work to the grahics card (which has 256 MB, a 7800GS). Is my assumption reasonable, or totally off course?

I can't answer the question. Some motherboards, opposite channels are slot 1 & 3 and 2 & 4, and some motherboards it is slot 1 & 2 and 3 & 4. That is why you have to look in your manual to find out which is the opposite channel.

If you lost it, every manufacturer has a PDF version online.

-S

Nono, i do not mean the opposite channels, my slots 1 and 3 make for 1 GB together, so obviously it is correct right now. I just wonder if I can mix the different RAM bar sizes, if now I do not buy another couple of 512s, but just one single 1 GB bar - additional to my now existing 2 512ers. :hmm:

Now FS X wouldn't agree on your last statement. :rotfl:

Yes you can mix different sizes, you just nead to pair them accordingly.
On my old p4 with an intel 875pbz motherboard, i had a dual channel configuration with 4 ram sticks: 2x512MB and 2x256MB.

I personally think that FS X is purposely detuned for XP. Someday, someone will figure it out since it miraculously is the only graphics app on the planet that happens to run better on DX10 than DX9.