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#1
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Why is DRAM voltage increased to over specification?
My memory Kingston KVR800D2N5 should run between 1.7 and 1.9 V.
but for some reason my GA-EP45-UD3L sets the DRAM voltage to 2.0 V. In the BIOS, the DRAM voltage setting says "1.8 Auto" even though EasyTune says it is at 2 volts. So I manually changed the Auto entry to 1.8, and now EasyTune says the DRAM voltage is correctly set at 1.8. Are there any other settings that the BIOS will automatically set too high? That happens without any overclocking. It was not corrected by changing "Turbo" to "Standard". Thanks. |
#2
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Why is DRAM voltage increased to over specification?
John Doe wrote:
My memory Kingston KVR800D2N5 should run between 1.7 and 1.9 V. but for some reason my GA-EP45-UD3L sets the DRAM voltage to 2.0 V. In the BIOS, the DRAM voltage setting says "1.8 Auto" even though EasyTune says it is at 2 volts. So I manually changed the Auto entry to 1.8, and now EasyTune says the DRAM voltage is correctly set at 1.8. Are there any other settings that the BIOS will automatically set too high? That happens without any overclocking. It was not corrected by changing "Turbo" to "Standard". Thanks. Motherboards do stuff like that, to try to ensure they can POST with a wide range of memory products. Such an approach would not be necessary, if the SPD on each DIMM represented conditions that a DDR2 DIMM would pass at JEDEC nominal 1.8V. It is the fact that the DIMM makers take shortcuts, that causes the motherboard maker to have to do stuff like that. If the motherboard maker doesn't do it, the result is more phone calls to Tech Support when a motherboard won't POST. The server motherboard and server DIMM industry, is more conservative, and you're more likely to see adherence to JEDEC conditions for both DIMMs and motherboards. In the desktop industry, it is a game of "liar's poker". Which means you have to "up the ante" to play. Gigabyte has decided that 2.0V is safe to use with any DIMM. (Your Kingston datasheet doesn't spec the "destruction voltage" for that DIMM. The JEDEC value of 1.8V is simply the recommended industry wide operating voltage. The 2.0V delivered, might not be doing any harm at all. We have no real way of knowing, since the memory industry doesn't toy with the idea of a "destruction voltage". They only choose to meet the JEDEC spec, and any room above that is gravy.) If you want to get technical about it, we could discuss the table on PDF page 23 here. http://download.micron.com/pdf/datas...r2/1GbDDR2.pdf That table contains "Absolute Max" values. Vdd is limited to 2.3 volts according to that. That could be an instantaneous failure value. But another operating point, might be somewhat closer to a "long term life" value, which might be a little bit lower than that. At least one semiconductor company, has some of its specs related to 100,000 hour operating life, so for excursions outside the norm, they sometimes guarantee an operating life under those set of conditions. In this case, of the Micron memory chip, it likely isn't destroyed instantly at 2.29 volts, but we don't know whether it will last quite as long as an identical chip operated at 1.8V for its entire life. At least that value of 2.3V, should give you some idea how much danger you were in, when the motherboard delivered 2.0V. A different manufacturer of memory chips, could have a value other than 2.3V in their table. ******* As for how many voltages could be adjustable on a motherboard, there could be eight or nine voltages that they could adjust. Just to give you some idea. Thankfully, adjustable regulators cost more money, so not every motherboard is that adjustable. The fewer adjustments, the fewer mistakes they can make. In general, it is pretty difficult to verify whether parts of your motherboard are being abused by boosted voltages. I doubt I could find all the voltages on my motherboard, that claim to be adjustable, and verify them with a multimeter. Even if they provided a copper pad with a label next to it, I'd be pretty happy with that as a means to verify the voltages. And that wouldn't cost them any money to do. There was one motherboard, that had "scope points" soldered to the board. Which is a little metal stand, with a cup shape in the end of it, to make it easy to poke with a meter probe. That is the closest I've seen, to a motherboard designer caring whether a user could verify their voltages. On all the motherboards I have here, there isn't any hint as to what the various regulator circuits are connected to. Or where is a good place to probe them. So if you wanted to verify the key eight or nine voltages, well, good luck to you. Paul |
#3
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Why is DRAM voltage increased to over specification?
John Doe a écrit :
My memory Kingston KVR800D2N5 should run between 1.7 and 1.9 V. but for some reason my GA-EP45-UD3L sets the DRAM voltage to 2.0 V. In the BIOS, the DRAM voltage setting says "1.8 Auto" even though EasyTune says it is at 2 volts. So I manually changed the Auto entry to 1.8, and now EasyTune says the DRAM voltage is correctly set at 1.8. Are there any other settings that the BIOS will automatically set too high? I wondered about that kind of behavior too. I had launched a thread named "EP35C-DS3R memory overvoltage control" on 20th of last october. (sorry: I don't know how to create a direct link towards a usenet article). For the record, in my case, I had to learn that the default setting of the motherboard created some errors with memeory (I had to redo the memtest to see that). After I lowered the voltage to the memory brand recommendation, there was no more errors. Not that I know. The EP35C-DS3R is the firt Gigavyte MB I bought, and it is also the first time I see such a picky attitude towards memory sticks (I had to change the first sticks I had bought, since they produced an amount of errors so high out iof incompatibility). Frankly, this is not a good point in favor of Gigabyte. But you have yo chose a MB, right? Huey |
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