1.5 GB of Ram in a MSI K8N Neo

[omega7]

I would like to be able to pop in a third stick of ram into my system since my roommate has an extra 512 mb dimm (we are wierd like that). I may not do this immediately, since I would have to give up my timings, but it would be great to know how to do this for whenever it is needed.
I have read on Anandtech (I think) that they were able to run three sticks of PC-3200 with this mobo at full speed by simply setting the memclock in the BIOS to DDR400. If I do this, the ram still boots up at PC-2700 speeds, which is the default setting with three. Maybe this is a bios problem. I am running the most up-to-date version as listed on MSI's website.
Another way I thought of doing it was to let it boot up at PC-2700 speeds and then overclock the FSB until the memory was running at, or close to 200. I figured out that if I put the FSB at 245, and change the CPU multiplier to 9, then everything should be well within stable operating frequencies:

CPU - 245 x 9 = 2205 (2.2 GHz is default)
HT - 245 x 4 = 980 (It is rated for 1 GHz)
RAM - CPU/11 = 200

The only problem is that if I set the FSB to 245 in BIOS, then the system will not post. If I let it boot to windows at 200, and then use CoreCenter to overclock it, then the system freezes around 230.
This is in accordance to my previous overclocking attempts with this mobo, where I get errors in Prime95 if I brought the FSB to 220, even with a lowered CPU multiplier. With my previous mobo, a VIA K8T800, I was able to hit close to 2.4 GHz with the same CPU, and my RAM ought to be just as capable.
This leads me to believe that it is a AGP/PCI lock error. Is there anyway to ensure that the locks are working, or is there something else that I should try? I am running two SATA drives in addition to what is listed below.
Thanks for your help.

 

[slash196]

I'm not too familiar with OCing, but I have read that overclocking with more than 2 sticks of RAM can be a real headache. It seems to me that if you can't run four sticks at stock speeds, then there's no point in having four slots, but that's just me.

 

[omega7]

Just as a clarifier, this is a socket 754 board, so it only has three single-channel ram slots. I also am pretty sure that it is not a heat issue, since I have a well-ventillated case, and I have replaced the stock passive northbridge cooler with an active one; but as I showed above nothing, except the FSB, is overclocked.

 

[Peter]

No way in hell three DIMMs will work properly at 200 MHz, particularly not if there are double-sided ones amongst those. Get on with it.

 

[customcoms]

I have the same problem-I can't get avbove 230,on the same board, whatever I do. Lower the HTT multiplier, up the voltages on the ram and cpu (on the cpu above what most people use to get 2.4 ghz on a 2800+). Decrease the ram ratio (will try more w/ this). Have the latest bios. I thought it was my power supply, since it is a crappy no-name 400 watter, but since you are having the same prob, on the same board, w/ a good-great psu, that doesn't seem to be it. I am running two dimms of Geil Value Ram, PC3200. Any suggestions from the experts?

Sam

 

[omega7]

I tried moving up the AGP frequency to 67 MHz hoping that this would ensure that the locks are enabled
and I was almost there. In windows, using CoreCenter, I was able to get to 245 FSB with Prime95 running, but after less than a minute, the computer froze.
It was at Anandtech that I saw the three dimms. Not sure if they were all double-sided, but here is the link:
http://www.anandtech.com/mb/showdoc.aspx?i=2036&p=6
I also notice that they achieved 246 FSB apparently without lowering any multipliers.
I know this is sort of turning into an overclocking thread, but the ultimate goal is to run 1.5 GB of RAM.

 

[omega7]

I think I figured out the FSB problem. I read in another forum that the pci lock does not work on the SATA 1/2 ports, and so I switched my two drives to SATA 3/4 and what do you know, it's working. The system has not yet frozen, and everything seems to be working fine. I will try it with three sticks of RAM as soon as possible.

 

[customcoms]

Well, I already have my drive in the sata 4 port (knew about this prob.). You have MUCH better ram, but I should be able to overclock to like 260 if I turn down the memory speed. I think what is holding me back is my crappy psu. Also, w/ the three dimms, make sure you get more of the same (OCZ). You really need to have all three identical dimms, and preferably double sided ones (not sure w/ the platinums, but they shoukd be fine), if you are overclocking like you are.

Sam

 

[omega7]

Okay, I got it to work, sort of. The third dimm from my roommate is just a generic one since I am not ready to spend $100+ on a matching one at this time. I got them to run at 200.5 MHz with a little extra CPU and RAM voltage. At 2-3-3-10 Prime 95 got errors in less than ten minutes. I relaxed the CL to 2.5 (the default on this third dimm) and Prime95 ran for almost thirty minutes before errors.
Benchmarks are about the same as before, but I have yet to check how this impacts game loads. I will probably not keep this setup since it isn't too stable as is, but it was nice to know that it is quite possible. Maybe later I will splurge on a better dimm and it ought to work fine even with tight timings.
If there are any ideas to how it might work better at these settings I am open to suggestions. It would probably work at CL 3, but that would be pointless to insult my two high-quality dimms like that since the extra ram wouldn't make that much of a difference now.