Question about RAM

[dragoncurt]

How fast does ram actually go in speed like MBs or GBs . thanks

[Chasem121]

depends on the ram. DDR3 1600 is around 12.8 GB/s

[dragoncurt]

depends on the ram. DDR3 1600 is around 12.8 GB/s

Oh thanks for the reply and that's what I don't get. How can it go that fast if you only have a ssd that goes around 500MBs.

[trag1c]

Very fast.

[trag1c]

Oh thanks for the reply and that's what I don't get. How can it go that fast if you only have a ssd that goes around 500MBs.

Although SSD's are using flash storage RAM and SSD's are still very dissimilar. They're using different technologies with very different use cases. 

[dragoncurt]

Although SSD's are using flash storage RAM and SSD's are still very dissimilar. They're using different technologies with very different use cases.

But how does the ram go that fast if you can only do reads of 500Mbs is it like for games where if will kepp the data for a while ?

[agent_x007]

But how does the ram go that fast if you can only do reads of 500Mbs is it like for games where if will kepp the data for a while ?

Two things : ​

1) CPU almost NEVER goes to SSD/HDD once program is loaded, most things he needs (at the moment), or will need (in near future), are kept in RAM or on-die cache.

2) Different controller (IMC is few times faster than DMI/HTT/FSB or other buses, and it's a completly seperate entity in newer CPU's).

Basicly : Once a program or data has been uploaded to RAM from SSD/HDD, U always get a full RAM speed read/write/latency when U try to access it (assuming IT, wasn't "paged" because of lack of RAM space).

[You_are_a_cunt]

I covered that in my RAM Buyer's guide: http://linustechtips.com/main/topic/495974-guide-ram-buyers-guide

 

answer is: depends on ram and frequency

[dragoncurt]

Two things : ​

1) CPU almost NEVER goes to SSD/HDD when program is loaded, most things he needs (at the moment), are kept in RAM.

2) Different controller (IMC is few times faster than DMI/HTT/FSB or other buses, and it's a different entity in newer CPU's).

Vast majority of data going in and out of the RAM isn't touching SSD/HDD at all.

Basicly : Once a program or data has been uploaded to RAM from SSD/HDD, U always get a full RAM speed read/write/latency when U try to access it (assuming it wasn't "paged" because of lack of RAM space).

But what data is needed to go around 10 gigs a second any way

[trag1c]

But what data is needed to go around 10 gigs a second any way

Everything.....Your computer would basically become unresponsive without that much data bandwidth.  Everything your processor operates on is stored in RAM because its capable of processing much more data than your SSD or HDD could provide in a single second. (theres more to it than that but thats the general idea.)

[agent_x007]

 

But what data is needed to go around 10 gigs a second any way

 

Well iGPU data for starters (a hundred GB/s would be nice to have in future iGPU's).

Then there's the MASSIVE bandwidth needed to keep Core's busy (we are talking 2 to 4 cores that are going 3,5GHz each).

IF we could, we would make all data levels equall in terms of speed and capacity, but we can't.

That's why we have cache levels (because more capacity = slower speed).
Since Core's are pretty much a part that is always needed, all the data that goes to them needs to go A LOT faster than 10GB/s.

 

PS. Check how fast is L1 cache (and how small it is).
If RAM bandwidth wasn't needed, we wouldn't see a difference between DDR3 1066MHz (in theory : 17GB/s in Dual Channel), and DDR4 3000MHz (~48GB/s in Dual Channel).

[dragoncurt]

Everything.....Your computer would basically become unresponsive without that much data bandwidth.  Everything your processor operates on is stored in RAM because its capable of processing much more data than your SSD or HDD could provide in a single second. (theres more to it than that but thats the general idea.)

Oh okay then. I did not know that as when I look at my ram when I first boot up it had used up 1gig

[Godlygamer23]

Oh thanks for the reply and that's what I don't get. How can it go that fast if you only have a ssd that goes around 500MBs.

Things are loaded into RAM from the storage drive. The RAM is then accessed by the CPU as needed, which includes not only reading from it, but also writing to it. Same goes with CPU cache. CPU cache is magnitudes faster than RAM.

[Godlygamer23]

But what data is needed to go around 10 gigs a second any way

All of it.