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Did I buy the right memory?


waynebretl

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Bought (4) CMX1024-3200PT for use in ASUS A8N-SLI Premium motherboard with AMD Athlon 64 X2 dual core 4800+. Seems to run OK with only 2GB installed, but with 4G, get random reboots/ stop errors. Should I be using a different model of mem modules?

 

Also, I don't know how to find settings for latency, but I assume that's around here somewhere. Have tried adjusting the voltage, which does not help.

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Ddi you test the system with http://www.memtest.org one set at a time, and do you have the latest bios and what are the exact settings you have set with all four installed?

 

1) I have the latest bios downloaded/installed.

2) Have not run memtest - Will run the test one at a time tonight

3) Can't find where to see/adjust the latency settings - bios does show voltage setting

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Ran memtest one stick at a time ( as suggested by ASUS), and all 4 test OK. Suspected as much, as things seem to run OK wiht any combo of 2 sticks installed.

 

checking latency settings:

parameter value with 2 sticks(OK), with 4 sticks(get crashes)

 

timing mode [auto] [auto]

memclock index value 400 MHz 333 MHz

cas# latency Tcl 3 3

min ras# active time (Tras) 8T 7T

ras# to cas# delay (Trcd) 3T 3T

row prechargte time (Trp) 3T 3T

row cycle time (Trc) 11T 10T

row refresh cyc time 13T 11T

read-to-write time (Trwt) 5T 4T

write recovery time (Twr) 3T 3T

1T/2T memory timing 2T 2T

S/W DRAM OVER 4G remapping [enabled] [enabled]

H/W DRAM OVER 4G remapping [enabled] [enabled]

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Have you thought about your power supply unit? It may not deliver enough +12V capacity to power your current configuration. You see, in the case of that Antec SP500 of yours, 17A plus 19A does not equal 36A due to loading issues in a PSU with multiple +12V rails. Its real combined +12V capacity is only about 29A - but that Radeon X1900XT needs a PSU with at least 32A combined on the +12V rail(s) even for single-card configurations.
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Have you thought about your power supply unit? It may not deliver enough +12V capacity to power your current configuration. You see, in the case of that Antec SP500 of yours, 17A plus 19A does not equal 36A due to loading issues in a PSU with multiple +12V rails. Its real combined +12V capacity is only about 29A - but that Radeon X1900XT needs a PSU with at least 32A combined on the +12V rail(s) even for single-card configurations.

 

Very good info RJLeong65, I did not catch that.

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Very good info RJLeong65, I did not catch that.

 

Not only that, but that SP500's 17A +12V1 rail is shared between the 24-pin ATX power, the peripherals, the SATA drives and the PCI-Express cards. The 19A +12V2 rail is used only for the 4-pin ATX12V P4-style connector. And unlike some of the newer-design multi-rail PSU's, the SP500 cannot reserve extra power from the +12V2 rail even if the +12V1 rail is already maxed out.

 

In other words, the X1900XT draws more power from that weaker +12V1 rail than it can handle -- which is why you're getting occasional stability issues, especially with 4 double-sided memory modules installed.

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Didn't have a chance to check power supply droop with 4 sticks, however, did some looking for power supply specs, and here's the problem: I have a note from ASUS recommending a power supply with 35A rating on the +5V. Most/all of the higher wattage supplies with multiple +12V outputs have lower +5 (and +3.3) ratings (typically 30A on the +5). So, I'm at a loss as to what supply really is proper for this mobo with full memory etc. The Antec supply has the 35A rating, but does the machine really use less 5V and need more 12V?

 

Any thoughts? I know the total +5 and +3.3 outputs are really limited to some lower value by a total watts rating, but don't know how to compare this to the ASUS supplied numbers - which output is really the power hog?

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Didn't have a chance to check power supply droop with 4 sticks, however, did some looking for power supply specs, and here's the problem: I have a note from ASUS recommending a power supply with 35A rating on the +5V. Most/all of the higher wattage supplies with multiple +12V outputs have lower +5 (and +3.3) ratings (typically 30A on the +5). So, I'm at a loss as to what supply really is proper for this mobo with full memory etc. The Antec supply has the 35A rating, but does the machine really use less 5V and need more 12V?

 

Any thoughts? I know the total +5 and +3.3 outputs are really limited to some lower value by a total watts rating, but don't know how to compare this to the ASUS supplied numbers - which output is really the power hog?

 

Your configuration simply needs more +12V capacity. But since there is no current multiple +12V rail PSU with a reasonably low overall wattage rating (or at a reasonable price point) which provides both high +5V capacity and a high +12V capacity, the only current way to get a suitable PSU for your config is to buy far more wattage than your system really needs (this means that you may need a 750W or higher-wattage PSU, and spend a relatively astronomical amount of money for such a unit, just to get sufficient capacity on both the +5V and +12V rails).

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I was afraid of that. Let the search begin!

 

I forgot to tell you that since you have some motherboard devices using the +3.3V rail, the +5V capacity of your current PSU will drop to 28A when both the +3.3V and +5V rails are being used. This is due to the fact that the +3.3V and +5V rails on your PSU both share the same tap, with a single commonly shared limiter for both rails.

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I've been running ASUS PCProbe now, and I'm seeing the same voltage reading variations with 2 sticks or 4 (readings set to update at max rate, once per second)

Core 1.36-1.38

3.3V 3.22-3.25

5V 4.92-4.95

12V 12.10-12.35

 

So, no evidence that the added memory is pulling down the 12 volts or anything else, although both the 3.3 V and 5V are a bit low in general. Of course, there could be some transients too short to see with the probe program.

 

Anyway, I have ordered an auxiliary 12V supply just to run the graphics card. Cheaper than a whole new humongous supply. It's a 300 watt (2x 150 watt 12 volt outputs) that fits in a spare 5 inch bay and is supposed to automatically turn on and off with the main supply. I'll see if that helps.

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Well, I have now tried the auxiliary 12 volt supply for the graphics card, and it still shows the problem. I don't see any point in changing the main supply, because it has higher ratings individually (amps) and combined (watts) for the 5V and 3.3 V than the one recommended above, and meets ASUS recommendations.

 

At this point, I think I will just run with 2GB RAM and sell the other two sticks, unless someone comes up with some really brilliant idea. The problem only occurs when running XP, not when testing with memtest, so it seems it must be an OS/driver bug that doesn't handle the full memory correctly.

:[pouts:

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