I have this motherboard and I have a few questions.
 
 
First, some background:
 
I spent a lot of money and effort into building my current PC, and I would like to get it as stable as possible.  I purposefully upgraded, deciding to build my own, thinking that I would get more bang for my buck (as opposed to buying a pre-built system from Best Buy, Dell, or whatevs) mostly with the intent to play the Sims 2.  My old PC just wasn't cutting it anymore.  I don't use my PC for much else, aside from browsing the web, e-mail, iTunes, the occassional download, and word processing.  About the only really intense program I ever ran was the Sims 2.  I do not do any video processing/editing.  I have used programs to convert my TiVo files to iPod format.  However, I would often get BSODs when I tried to run several programs at the same time, or tried to play the Sims 2.
 
I mentioned these problems previously.  It turned out to be a heatsink/thermal paste issue, which I resolved by purchasing a totally new heatsink.  The temps have significantly lowered, and my PC seemed to be more stable.  However, I was still having some BSOD issues.  After posting on various boards and asking for help from other peeps online, I was told that the issue may be related to timing and BIOS settings.  I stepped down the timing in my BIOS and my PC now seems to be a lot more stable.  I have not had a BSOD in at least over a month or so.
 
I believe the problem is that the RAM I originally purchased has lower timing than what I am certain was originally stated on newegg.com - I may be imagining it, but I am pretty sure the website had said it was 5-5-5, but it now lists the ram as 4-4-4.
 
 
As such, I want to maximize the performance of my PC, and I am looking to get RAM with 5-5-5 timing, which I assume is better.  However, I have some concerns, as I reviewed the manual for my mobo, and it states the following:
 

 
 
I sought advice from someone I consider a PC expert on one of the other forums that I frequent.  He explained that, despite what people have said, the WinXP 32-bit OS is capable of using 4GB of RAM, it just reports it funny, usually saying it only sees 3.5GB.  But, all secondary RAM readers that he has used all report the full 4GB of RAM.
 
 
He explains that there can be limitations that are hardware specific.  I'm wondering if anyone here may have experience with this mobo and know the following:
 
1)  Will this mobo support 4GB of RAM with WinXP 32-bit OS?
 
2)  Does the RAM have to be DDR2-667 or DDR2-533 only, if I use 2GB sticks?
 
3)  If use 4 x 1GB sticks, then will DDR2-800 still be ok?
 
The reason I am asking these questions is, I want to upgrade to 4GB of RAM now, with the possibility of going higher if I upgrade to Vista.  Having said that...
 
4)  Would this mobo even support Vista?
 
I was told that Vista Home can see up to 8GB, which is the max memory that the mobo can support anyways.  But since the manual doesn't list it in the memory section, I am wondering if I will run into problems and be forced to have to build a totally new system if I want Vista.
 
 
I am looking at getting mushkin as I was told their brand is very good, high quality, gaming memory.
 
If anyone has any other recommendations, feel free to let me know.  I would greatly appreciate any advice.  Thanks.
 
 
- Ste

Answers are as follows:
 
1. No; no motherboard will (your friend is, respectfully, incorrect).
2. No; it is highly reccomended that they are of the same speed rating, but it is not required that they be.  Your faster memory will simply adjust its timings to run at the slower modules speed.
3. Yes; however you may have to bump up the voltage .1v or so for stability.  As an aside, if installing from a non-SP1 Vista DVD you will need to pull two of the modules to install without generating a BSOD (Vista errors when performing an install with more than 2GB of ram without KB929777(-v2-x64) already installed.  Vista SP1 installation media rectifies this issue.
4. Absolutely; we have several in our Studio that run Vista Ultimate x64 with 8GB using Q6600's OC'ed to 3.2 extremely stable (stable enough to render 3D animations 24x7).
 
Mushkin is solid; Patriot, OCZ, and Corsair,  are arguably a tad higher on the enthusiast's scale currently.

 
Just to be clear about the 2nd question, what I meant was... if I eventually wanted to go with 2GB of RAM per slot, can I only use either DDR2-667 or DDR2-533 only?  Assuming all sticks are the same frequency/timing/speed/whatevs... in other words, if I did want to go up to 8GB of RAM total (meaning I would have to use 2GB sticks per slot), is it absolute that I cannot use DDR2-800?
 
In your case, you say you have PCs that are running Vista with 8GB of RAM.  Are you using DDR2-800 sticks?
 
 

 
When you say, bump up the voltage to .1v... do you mean that the memory sticks should have a higher voltage rating?  Or are you telling me that I need to upgrade my PSU?  Currently, I have a 550W PSU.
 
 
The specifications for this ASUS mobo say:
 

 
This comes from newegg.com.  I read this to mean that the mobo only supports memory sticks rated specifically at 1.8V with 5-5-5 or 6-6-6 timing.  Are you saying that I can use a stick that has a higher V rating without problems?
 
 
 

 
I'm looking at the list for those brands, and there don't seem to be many that are 1.8V and have a 5-5-5 or 6-6-6 timing?  Is the "Notice" (that I mention above) a warning that is specifically for DDR2-800 only?  Meaning, if I want to use DDR2-800 memory, then the voltage must be 1.8V?  Is that a maximum?  Or a minimum?  Meaning, can it be 1.8V rating or higher?  Or, the ram must specifically be rated at 1.8V or in a range that includes 1.8V (since newegg.com lists some RAM as being 1.8-2.0V or 1.8-2.2V).  In other words, can I use any ram that is at least 1.8V or within any of those ranges?  Or, is the voltage just a minumum suggestion as opposed to a hard and fast rule?
 
Also... what about timing?  If it's DDR2-800, it must have a timing of 5-5-5 or 6-6-6?
 
 
Assuming I stick with WinXP for now, how concerned should I be when it comes to:
 
Cas latency?  Timing?  Are they related?  What are they anyway?
 
Voltage?
 
Heat Spreading? (I have no plans to overclock)
 
 
Again, thanks for the information.
 
 
Ste

The warning about only using 1.8V 5-5-5 or 6-6-6 RAM is a general warning for all boards using the P965 chipset.  You can use faster RAM, but you'll need to manually set it up in BIOS.  When set to auto in the BIOS, DDR2-800 RAM will automatically be set to 1.8V, 5-5-5 timings, and probably DDR2-667 speed.  This ensures the board will boot the first time.  You then go into BIOS and set the RAM up.  Once you get the RAM setup, run memtest86 for a few hours to verify the RAM is running OK.
 
BTW, the lower the timings the better.  4-4-4 is faster than 5-5-5.

I have an asus p5b and recently bought 2 1 gig sticks of 800 ddr2 crucial ballistics to upgrade from 2 512mb sticks 533 ddr2.  I will put another 2 gigs in the near future. Your motherboard will support it.  
 
side note I went into the bios and change my timings to 4-4-4-12 from the default of 5-5-5-15. like rqpritchett said.  that is what the ram is rated for.
 
I have run xp32bit,xp64bit,and vista32bit on this board.  I probably will upgrade everything before i get to vista 64bit but it would work fine.  
 
you can go with ddr2 800 2 gig modules and with a bios update I believe you could go with 1066.  
 
Any of the memory listed before would be a fine choice.

I have a P5B Deluxe WiFi/AP wit 8 Gig of RAM. I have 2 sets of OCZ Platinum DDR2-1000 (OCZ2P10004GK) Upon Boot up It defaults to DDR2-667. It overclocks to 850 Without a problem. If you are getting 2 Gig sticks most will work out of the box. You may have to raise the voltage to get them stable if you use tight timings.
 
With a full 8 gigs in the P5B you will not overclock them as high as 4 1 gig sticks. With the P5B if you install 4Gigs and have a 32bit OS you should turn off the memory remapping inthe BIOS under chipset. This will allow the OS to see 3 Gig(3008). If you turn it on with a 32bit OS you will only see 2.5 gig(Not sure why you dont see 3.5 Gig like other Chipsets). This is a limitation of the P965 Chipset. Right now RAM is cheap but if you want 4 Gig or over you need a 64Bit OS.
 
I have Vista Ultimate 64Bit and runs great. I did use Vista x86 with 4 Gig with the memory remapping turned off.  
 
If you are having random BSOD first download Memtest86 and test the memory you have now. If you have any errors it could be bad RAM or you might have to bump up the voltage or play with the timings. If you have the RAM Configure DRAM timing by SPD in the BIOS you may have BAD RAM if you set the Timings manually then you may have entered the wrong timings.
 
If you set them manually then enable Configure by SPD in the BIOS.
 
Also what BIOS version are you running? I had a problem with the board with 4 1Gig sticks not working until a BIOS update.
 
1Haplo

i also have the P5B deluxe with 4gb Geil ultra low 4-4-4-12 which i manually changed the voltage to the recommended 2.1v, the 1.8v is the minimum for ddr2 i think.

 
Oh!  I see.  Thanks,  I did not realize that.  What about the 4th number?  I sometimes see newegg.com list 5-5-5-18 and 5-5-5-15 for example.  Is the 15 better than the 18?
 
 
 

 
Ok, so the mobo will support 4 x 1GB sticks, if they are DDR2-800.  My question is... if I want use 2GB sticks instead, is the notice a strict warning?  Meaning, IF I use 2GB sticks, then they MUST be 667 (or 533)?  Or again, is that merely a suggestion, which can be overcome if I just have the proper BIOS settings?
 
 
 

 
Well... I only have a P5B.  No E, no Deluxe, nothing else.  Would this still work for me?  And... I assume that, by raising the voltage, this is a setting I can change in the BIOS?
 
 
 

 
 
Thanks for the explanation.  Would it even be worth it then, to have 4GB of RAM installed, in the form of 2 x 2GB sticks?  Even if I turned off the memory remapping in the BIOS, like you said?
 
Or would it be better to just have 3 x 1GB sticks (for a total of 3GB)?
 
 

 
Hrm... I may have to look into this.  I don't remember exactly what I did.  I was just following instructions that a friend told me.  I remember having to pick lower numbers, but I forget if that was timing.  I'm guessing it was.  I think I left the other values default (voltage).
 
BEFORE I changed the BIOS settings, I did run memtest86 extensively (over night) on my RAM, and it produced no errors.  I was still getting random BSODs.  I also seemed to get BSODs after awhile, when I tried to play The Sims 2, and usually, whenever my antivirus program tried to update itself overnight (I typically leave my 'puter on all the time, and when I wake up, it often had a BSOD, which I assume was related to it trying to update the anti virus program over night, and most likely causing intensive CPU strain or creating intensive heat.  The problems seemed less frequent, after I got the new heat sink, but then they came back.  AFTER I changed the BIOS settings (as instructed by my friend) my PC seems to run a lot better, and I haven't had a BSOD in probably over a month, if not longer.
 
 

 
 
I am currently running WinXP Home 32-bit version.  Which I guess means I am SOL and cannot use > 2GB of RAM?
 
 
Ste

If you put 3 sticks of RAM in the board, The RAM would not run in dual channel. Its better to run 4 x 1 Gig sticks or 2 x 2 Gig with Mapping on. Then it will run in dual channel.
 
To update your BIOS go to ASUS and download the newest BIOS, Then enter the BIOS and under tool is ASUS EZ Flash. That will update the BIOS from the file you download from ASUS, the one on ASUS for the P5B is BIOS version 1803. It has nothing to do with Windows or any OS.
 
I have seen some BIOS updates that help stability.
 
Also OCZ has a great Forum for the RAM. They have settings that they recommend for the RAM and Chipsets.  
 
Yes in RAM timinhs lower numbers are better IE 4-4-4-15 is better then 5-5-5-18. But lower numbers may cause instability if not used proper. Just becasue you can choose 4-4-4-15 in the BIOS does not mean it will work. Just beacuse the memory is rated at 4-4-4-15 it may not run at that speed on your motherboard.
 
You can get 4 X1 Gig of DDR2-800 and it will run at 800 no problems. Its just the 2 Gig sticks. If you are going to keep a 32bit OS then the 4 X1 will be perfect for you. Unless you will be getting a X64 OS then get the 2 Gig sticks. I would not get the 2 gig sticks unless you are going with a 64 bit OS. because you will never get a second set unless you have a 64bit OS.With the prices right now just stick with the 4 X 1 Gig sticks. If you want to use Vista and want to the 64 bit then i would get the 2 gig sticks.
 
1Haplo
 
 

 
I assume that mapping is an option in the BIOS, right?
 
 
 

 
Would I need to flash the BIOS if I'm sticking with a 32bit OS for now and want to use 4x1 Gig?
 
I thought the limitation of seeing the full 4 GB of RAM is a characteristic of WinXP.  But are you saying then, if I flash the BIOS, I can get WinXP to see and actually use all 4GB of RAM?
 
ATM, I will probably stick with WinXP, since that really is all I need for now.  But I would like to think about the possibility of upgrading in the future.  But, I suppose... by the time that rolls around... it may be best to build a new rig anyways...  
 
 
Ste