Memory question

[Dethanu]

So i had to reset my CMOS battery since my PC turned on but there was no video signal from the computer. Now my DDR3 is set to 400Mhz from 800. Can i change these settings without totally crashing this PC?

 

RAM

[Streetguru]

13 minutes ago, Dethanu said:

 

it'll report half the speed because that's how dual channel memory works. You should probably run the XMP profile if that's a thing anyways because that RAM speed is really low

If you have 2 sticks it's running at 800mhz now, if it was reporting 800mhz before with 2 sticks, your RAM was running at 1600mhz

[Cyracus]

yeah, set xmp profile in bios or if you have the speed and timings available (sticker on ram or from packaging when you bought the ram) you could set it manuallydouble check whether it displays as half in the bios (1333 should be the lowest, if it shows 667-800-etc then set it at half the rams rated speed)

[kb5zue]

4 minutes ago, Cyracus said:

yeah, set xmp profile in bios or if you have the speed and timings available (sticker on ram or from packaging when you bought the ram) you could set it manuallydouble check whether it displays as half in the bios (1333 should be the lowest, if it shows 667-800-etc then set it at half the rams rated speed)

You did not say whether your system was Intel or AMD.  If my understanding is correct, XMP only applies to Intel mobos.

 

[Streetguru]

3 minutes ago, kb5zue said:

You did not say whether your system was Intel or AMD.  If my understanding is correct, XMP only applies to Intel mobos.

 

Works on both if I'm not mistaken, even on AM3+

[Cyracus]

2 minutes ago, kb5zue said:

You did not say whether your system was Intel or AMD.  If my understanding is correct, XMP only applies to Intel mobos.

well it's not my system, and I did include a bit about setting it manually. Figured it went without saying that if no xmp setting it'd have to be done manually

[kb5zue]

Just now, Cyracus said:

well it's not my system, and I did include a bit about setting it manually. Figured it went without saying that if no xmp setting it'd have to be done manually

Not necessarily.  If you have a current Intel system, the XMP allows the user to use a predescribed sort of settings bypassing the need to do things manually.  If you disable XMP, you can do them manually anyway, just like AMD because AMD does not have an XMP capability unfortunately.

[Clockwork_princess]

1 hour ago, Streetguru said:

Works on both if I'm not mistaken, even on AM3+

 

1 hour ago, kb5zue said:

Not necessarily.  If you have a current Intel system, the XMP allows the user to use a predescribed sort of settings bypassing the need to do things manually.  If you disable XMP, you can do them manually anyway, just like AMD because AMD does not have an XMP capability unfortunately.

intel has XMP and AMD has AMP, same thing different name, i think only certain BIOSs have it.  

[Streetguru]

11 minutes ago, Clockwork_princess said:

 

intel has XMP and AMD has AMP, same thing different name, i think only certain BIOSs have it.  

I don't think anyone actually used AMP, because of how much FX failed

so AMD just used XMP anyways

 

[NelizMastr]

2 hours ago, Streetguru said:

it'll report half the speed because that's how dual channel memory works. You should probably run the XMP profile if that's a thing anyways because that RAM speed is really low

If you have 2 sticks it's running at 800mhz now, if it was reporting 800mhz before with 2 sticks, your RAM was running at 1600mhz

The amount of channels has nothing to do with the rated speed, just with the bus width. Single channel memory operates at 64-bit, dual channel at 128-bit, triple is 192-bit and so on.

 

The effective speed is doubled because D(ouble)D(ata)R(ate) memory can perform two memory operations per clock pulse. So while the memory bus runs at 800MHz thus capable of 800MT/s, DDR memory can perform two operations per Hertz resulting in an effective capacity of 1600MT/s.