RAM not running advertised speed

[Nicnac]

Hey guys, I have a pretty dumb question. I recently got a gigabyte b450 sh2 that i paired with a ryzen 5 2600 and 16 gb of corsair vengeance lpx 3200mhz ram.

In the bios I selected the xmp setting and saved but still CPU-Z only shows me 1596.2 mhz in the dram frequency tab.

What else can I do?

TIA!

[TheGlenlivet]

1 minute ago, Nicnac said:

Hey guys, I have a pretty dumb question. I recently got a gigabyte b450 sh2 that i paired with a ryzen 5 2600 and 16 gb of corsair vengeance lpx 3200mhz ram.

In the bios I selected the xmp setting and saved but still CPU-Z only shows me 1596.2 mhz in the dram frequency tab.

What else can I do?

TIA!

That is 3200MHZ.  DDR shows half speed in CPUZ.

[minibois]

Just now, Nicnac said:

corsair vengeance lpx 3200mhz

[...]

1596.2 mhz 

TL;DR: your RAM is running at the correct speed.

 

RAM actually runs at 1600Mhz, that many ticks a second (in millions).

It's just every 'tick' it transfers two packages (that is why DDR = double data rate), so manufacturers of RAM/motherboards just call it 3200Mhz. It's actually 3200MT/s. transfers a second (times 1 million).

[Nicnac]

2 minutes ago, TheGlenlivet said:

That is 3200MHZ.  DDR shows half speed in CPUZ.

 

1 minute ago, minibois said:

TL;DR: your RAM is running at the correct speed.

 

RAM actually runs at 1600Mhz, that many ticks a second (in millions).

It's just every 'tick' it transfers two packages (that is why DDR = double data rate), so manufacturers of RAM/motherboards just call it 3200Mhz. It's actually 3200MT/s. transfers a second (times 1 million).

God damn i never knew lol! Can you guys point me to some good reading so I can fix my knowledge gap?

[TheGlenlivet]

1 minute ago, Nicnac said:

 

God damn i never knew lol! Can you guys point me to some good reading so I can fix my knowledge gap?

I'd say you are in the right place now, at least to start.

I've learned a lot from these forums and have gone from the helpee to the helper over the last few years.

 

[minibois]

24 minutes ago, TheGlenlivet said:

That is 3200MHZ.  DDR shows half speed in CPUZ.

Keep in mind CPU-Z doesn't just 'shows half speed', it's more like the memory manufacturers show double the speed.

They do this because every Mhz (tick) = 2 transfers. So one might argue the effective Mhz is 3200Mhz, but it's still only doing 1600 ticks a second:

Quote

This means that a 2666 MT/s DDR4 stick of RAM actually operates at a base speed or frequency of 1333 MHz. However, due to it completing double or two operations per cycle, it operates as if its frequency is 2666 MHz. But this is technically not correct because MT/s properly represents the actual number of transfer operations that occur rather than the frequency in MHz. MT/s is essentially the effective MHz and should be used rather than MHz.

https://www.techsiting.com/mt-s-vs-mhz/

 

It's like you have two people, one carrying 1 bag of groceries, the other carrying 2 bags of groceries.

Neither does two steps at a time, but the person carrying 2 bags of groceries is effective 'outputting' (carrying) a result that is equal to that first person carrying 1 bag of groceries. But just because his effective output is 2 bags of groceries moved per step, it doesn't mean he suddenly does two steps at a time.

 

Sorry if I didn't put in words correctly what I am thinking, but 'CPU-Z shows half the speed' is very easy for people to understand, but also incorrect, which I wanted to elaborate on.

21 minutes ago, Nicnac said:

God damn i never knew lol! Can you guys point me to some good reading so I can fix my knowledge gap?

 This is just one of those things you find out one day, not really something I would classify as a 'knowledge gap'.

Just remember 1600Mhz is the actual output, but 3200Mhz is the effective output, because it does two transfers per Hz.

 

[TheGlenlivet]

4 minutes ago, minibois said:

Keep in mind CPU-Z doesn't just 'shows half speed', it's more like the memory manufacturers show double the speed.

They do this because every Mhz (tick) = 2 transfers. So one might argue the effective Mhz is 3200Mhz, but it's still only doing 1600 ticks a second:

Agreed.

I was just trying to make sure @Nicnac knew his XMP was working! hehe

 

[minibois]

3 hours ago, TheGlenlivet said:

Agreed.

I was just trying to make sure @Nicnac knew his XMP was working! hehe

Sure, telling someone it's working is good, but saying "CPU-Z shows half the speed" is incorrect. 

Your answer was correct, your reasoning was not. That was mainly what I was going for.