DigitalDJ Posted November 1, 2007 Share Posted November 1, 2007 Hi, I have P5K Deluxe/WiFi-AP and 4 sticks of CM2X1024-8500C5D. I bought these as two separate packs....One with the Dominator Fan, the other without (so I didn't have to pay extra for a fan I wouldn't use). I have tried to use all 4GB of RAM in this motherboard with BSODs occurring at least twice a day. I scaled back to 2GB of RAM and the motherboard was stable for several days....until it BSODed again, and then wouldn't POST... I RMAed my motherboard once, and got told it POSTed fine, got it back, and a week later it did the same thing. RMAed it again and I'm now waiting for a replacement. I don't think the RAM is at fault as even with all 4GB of RAM in the motherboard, MemTest86+ ran for 24 Hours with no errors. Tested with 2GB and then each 1GB individually...no errors. Are there any compatibility issues with the P5K, especially with using 4GB of RAM? The other main question I have is: Since I bought two different packs of RAM, the other day I realised the stickers were different (even though they're exactly the same model)... On two modules it says the following: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-18 XMS8505v1.2 07250748 The other two modules say: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-15 XMS8505v1.2 07200702 Why is one set of RAM rated at 15 and the other 18 when they're the same revision? Also what do the numbers at the end mean (07250748 and 07200702)? Could this partially be the reason why it was so unstable with all 4GB of RAM? Thanks, Grant Edit: As for testing the motherboard...I took it out of the case, reset the CMOS with Jumper/Taking out battery (even replaced the battery). Tried it with a different video card, an older P4 CPU and a lower 350W PSU (that works perfectly fine for a Media Center I have). Also tried each 1GB stick in each different slot (surely all 4 modules can't be faulty) Link to comment Share on other sites More sharing options...
DerekT Posted November 1, 2007 Share Posted November 1, 2007 I have tried to use all 4GB of RAM in this motherboard with BSODs occurring at least twice a day. I scaled back to 2GB of RAM and the motherboard was stable for several days....until it BSODed again, and then wouldn't POST. The memory controller can not keep up with the extra DRAM at the rated 8500 speed. You will need to drop the speed of the DRAM from 1066Mhz to 800Mhz. If you had purchased 4 X 1024MB of PC6400 (800Mhz) DRAM, then you would have had to drop to PC5300 (667MHz) DRAM, etc. 2 X 2048 will not issue this problem. This is a problem of all 4 banks being populated. Think of it this way. If you have a small phone book, then when you go into the index to find the page where you will find the phone number you are doing so at a certain speed due to the pages of the Index. Then you have to drive through the pages to get to the number. Now if your index is twice as large and the pages twice as many, then it takes longer to access the data. Now DRAM has a Strobe and the length of the strobe is how long the rows and columns can be left open before they must be refreshed. There is not enough time for the dram to be refreshed and then accessed with 4GB at the full access speed of the DRAM. The chipsets are optimized for 2GB, not 4GB and for 2 DRAM slots, not 4 DRAM slots populated. You can overclock the FSB (and hence the Memory Controller Hub = MCH) to gain some extra bandwidth and thus access the capabilities of the DRAM since the chipset is now clocked up. Usually when you clock up the FSB and concurrently the Memory Controller Hub (MCH) you need to raise the voltages of the CPU/MCH a bit as well. It's all a bit of a dice throw when you run with four banks populated. You need to test and find out what your board will accept. No two boards react the same. You overclock and tweak and try to get them to an acceptable throughput. My advice? Don't expect it. Hope for it, yes. But not expectation that you will get 1066. The issue is NOT the DRAM. The issue is the onboard Northbridge (MCH) and it's dislike of running at high frequencies with a population of four banks. I have seen people finally make stability, only to lose it months later. I have seen yet others damage the DRAM running too much voltage through trying to reach stability with 4 banks populated and trying for the full throughput of 2 banks populated. Another way to think of the issue is that the memory controller is optimized for 2 banks populated, not 4 banks. The que is now twice as long for data retrieval. The doors to the DRAM data are being opened and closed at the rate of the optimal 2 banks que and you are trying to make the Northbridge do double duty as fast as it does single duty. Often this leads to data corruption with doors being closed before data is fully retrieved or stored. I RMAed my motherboard once, and got told it POSTed fine, got it back, and a week later it did the same thing. RMAed it again and I'm now waiting for a replacement. This actually makes sense for they will not test with four DRAM banks populated. They will test with two banks populated. If they do test with 4 banks, they will drop the DRAM throughput. I don't think the RAM is at fault as even with all 4GB of RAM in the motherboard, MemTest86+ ran for 24 Hours with no errors. Tested with 2GB and then each 1GB individually...no errors. Are there any compatibility issues with the P5K, especially with using 4GB of RAM? The issue is the on board Memory Controller Hub (MCH/Northbrige) needs more time for storage and retrieve. The other main question I have is: Since I bought two different packs of RAM, the other day I realised the stickers were different (even though they're exactly the same model)... On two modules it says the following: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-18 XMS8505v1.2 07250748 The other two modules say: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-15 XMS8505v1.2 07200702 Why is one set of RAM rated at 15 and the other 18 when they're the same revision? Also what do the numbers at the end mean (07250748 and 07200702)? Could this partially be the reason why it was so unstable with all 4GB of RAM? The programming of the SPD was set differently. The 5-5-5-15 is the Corsair Spec and the 5-5-5-18 is the JEDEC spec. This would not effect the stability. That is the population of the four DRAM banks and the memory controller's inability to access those 4 banks at the speed of 2 banks. Sorry for such a long read. I tend to be a bit long winded. If you need a better explanation, please pm me with your messenger details. RAM GUY will explain this better than I can. :) He's the DRAM GURU :D: Link to comment Share on other sites More sharing options...
DigitalDJ Posted November 1, 2007 Author Share Posted November 1, 2007 The memory controller can not keep up with the extra DRAM at the rated 8500 speed. You will need to drop the speed of the DRAM from 1066Mhz to 800Mhz. If you had purchased 4 X 1024MB of PC6400 (800Mhz) DRAM, then you would have had to drop to PC5300 (667MHz) DRAM, etc. 2 X 2048 will not issue this problem. This is a problem of all 4 banks being populated. I probably should have mentioned that I also dropped the RAM to 667 and also had the problem. Do you think putting it up to 800 would maybe make a difference? The chipsets are optimized for 2GB, not 4GB and for 2 DRAM slots, not 4 DRAM slots populated. I would have thought seeing as P35 was new it would be more optimized to take 4GB of RAM, my understanding certainly has no proof behind it, but that's just what I thought :[pouts: The programming of the SPD was set differently. The 5-5-5-15 is the Corsair Spec and the 5-5-5-18 is the JEDEC spec. It's good to know that this won't affect stability, but I'm still sort of curious as to why the exact same model of the RAM has different labels (just because they came from different packs) :S Sorry for such a long read. I tend to be a bit long winded. If you need a better explanation, please pm me with your messenger details. Thank you for the informative information!! :biggrin: Link to comment Share on other sites More sharing options...
DerekT Posted November 1, 2007 Share Posted November 1, 2007 I probably should have mentioned that I also dropped the RAM to 667 and also had the problem. Do you think putting it up to 800 would maybe make a difference? Yes, actually you can run the DRAM too slow and can also run into error issues. I would have thought seeing as P35 was new it would be more optimized to take 4GB of RAM, my understanding certainly has no proof behind it, but that's just what I thought The problem is that the banks can not be optimized to run at 4 as they did with two. This is why the issue is across the board (pardon the pun) with both Nvidia and Intel chipsets. If you had DDR3, 1600MHz DRAM, and four sticks, you would have to drop again. Overclocking the FSB and MCH can bring back some of that bandwidth though. It's good to know that this won't affect stability, but I'm still sort of curious as to why the exact same model of the RAM has different labels (just because they came from different packs) RAM GUY will explain this to you and I will pop in to find the answer as this is just what I think. Do not take what I said regarding the two timings as written in stone. RAM GUY has the chisel on that particular event. :) IThank you for the informative information!! You're very welcome. If you have the problem with 800Mhz, then I would raise the MCH voltage 0.5V. and see if that helps. What voltage is your Vdimm set at? Link to comment Share on other sites More sharing options...
DigitalDJ Posted November 1, 2007 Author Share Posted November 1, 2007 What voltage is your Vdimm set at? I set it to what was in the PDF for the RAM (http://corsairmicro.com/_datasheets/TWIN2X2048-8500C5DF.pdf) 2.1V Link to comment Share on other sites More sharing options...
DerekT Posted November 1, 2007 Share Posted November 1, 2007 Try these settings as with 4 banks you do need a little bit more juice. AI Overclocking: Manual CPU Ratio Control: Manual CPU Ratio: 10 FSB Frequency: 266 PCI-E Frequency: 100 DRAM Command Rate: 2T DRAM Frequency: 800 FSB Strap to Northbridge: 266 DRAM Timing Control: Manual CAS# Latency: 5 RAS# to CAS# Delay: 5 RAS# Precharge: 5 RAS# Activate to Precharge: 15 TWR: Auto TRFC: Auto TWTR: Auto TRRD: Auto TRTP: Auto DRAM Static Read Control: Disabled Transaction Booster: Auto Clock Over-Charging Mode: Auto CPU Spread Spectrum: Enabled PCIE Spread Spectrum:Enabled CPU Voltage: Auto CPU Voltage Reference: Auto CPU Voltage Damper: Enabled CPU PLL Voltage: Auto DRAM Voltage: 2.2v FSB Termination Voltage: Auto North Bridge Voltage: 1.4 North Bridge Voltage Reference: Auto South Bridge Voltage: Auto Run your system as usual and let me know how it turns out. What cooling are you using on your CPU? Link to comment Share on other sites More sharing options...
DigitalDJ Posted November 1, 2007 Author Share Posted November 1, 2007 Try these settings as with 4 banks you do need a little bit more juice. Run your system as usual and let me know how it turns out. What cooling are you using on your CPU? As soon as I get the board back I'll try and give this a go. On the CPU I have a ThermalRight Ultra-120 eXtreme with a 120mm Scythe fan on it. Temps have never ever been above 55-60 under load. I've had Prime95 on all 4 cores running successfully with no errors for 48 hours at one stage. Link to comment Share on other sites More sharing options...
DerekT Posted November 1, 2007 Share Posted November 1, 2007 As soon as I get the board back I'll try and give this a go. On the CPU I have a ThermalRight Ultra-120 eXtreme with a 120mm Scythe fan on it. Temps have never ever been above 55-60 under load. I've had Prime95 on all 4 cores running successfully with no errors for 48 hours at one stage. Then you might wish to post in the Enthusiast section and I can help you to gain some of that lost bandwidth back. Certainly your system should be able to move up to 900/950Mhz. Link to comment Share on other sites More sharing options...
DigitalDJ Posted November 2, 2007 Author Share Posted November 2, 2007 Hi, The other main question I have is: Since I bought two different packs of RAM, the other day I realised the stickers were different (even though they're exactly the same model)... On two modules it says the following: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-18 XMS8505v1.2 07250748 The other two modules say: CM2X1024-8500C5D XMS2-8500 1024MB 1066MHz 5-5-5-15 XMS8505v1.2 07200702 Why is one set of RAM rated at 15 and the other 18 when they're the same revision? Also what do the numbers at the end mean (07250748 and 07200702)? A bump, Does anyone know the answer for this? RAM GUY? Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted November 2, 2007 Corsair Employees Share Posted November 2, 2007 Its just a miss print on the label the tested settings are Cas 5-5-5-15, and with 4 modules DDR800 would be suggested. Link to comment Share on other sites More sharing options...
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