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Slower ns timing will ALWAYS equal faster memory

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wanna_b_rich_13

Member
Joined
Dec 15, 2003
Will Slower ns timing will ALWAYS equal faster memory

Is the ns speed of memory directly affected with the memory speed in MHz?

Just to make sure that sounds right I am asking..
For ex.

Say a card is running 2.5ns @ 200Mhz

if you OC it to 2.4ns and it reachs 300MHz then in theory going to 2.3ns would give it another 100MHz or 400Mhz total?

Is it possible to have 2.5ns memory from two different manufacturers running at different speeds? Sort of implying one card's memory speed is either more underclocked or overclocked than the other manufacturers?
 
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johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
Well, you can't "overclock" a chip's ns rating. It's a constant - for example, the RAM on my video card is 3.3ns. I can't change that.

A chip's ns rating has a direct impact on total MHz, but it's not always exact. Two different companies that both make, say, 5ns chips won't always get the same clockspeed. Brand A could possibly hit 230mhz with their chip, while Brand B could maybe only do 200mhz at loose timings, or whatever. Does that make sense?
 

JigPu

Inactive Pokémon Moderator
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Jun 20, 2001
Location
Vancouver, WA
You can think of the ns rating as a measure of time the memory will complete one clock cycle in. Rather than specify how many clock cycles it completes in one second, they just tell you how long one cycle will take.

Like johan said, two chips rated with the same ns probably won't overclock the same. It's like two RAM sticks that are both rated for 266MHz operation, but both overclock differently, or run differently depending on timings.

Since ns is just a rating, manufactures tend to underclock them so they'll be garunteed to work. For example, my 9500 shipped with 3.3ns Infinion @ 275MHz. Based on the ns rating, the chip should handle 303MHz (1000/3.3) which it turns out is the exact limit of my OC unfotrunatly :(

JigPu
 

Overclocker550

Member
Joined
Feb 5, 2002
I had a 4ns ti4200 that only did 525 on the ram and another one thatll do 600MHz. ns isnt everything, the quality of ram is and 128mb ti4200s suck unless its albatron *or* the ram is BGA which is rare for ti4200s but the asus ti4200 im getting does have bga ram ;)
 
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wanna_b_rich_13

Member
Joined
Dec 15, 2003
johan851 said:
Well, you can't "overclock" a chip's ns rating. It's a constant - for example, the RAM on my video card is 3.3ns. I can't change that.

A chip's ns rating has a direct impact on total MHz, but it's not always exact. Two different companies that both make, say, 5ns chips won't always get the same clockspeed. Brand A could possibly hit 230mhz with their chip, while Brand B could maybe only do 200mhz at loose timings, or whatever. Does that make sense?

If you underlcock your card then won't that allow you to lower your ns timings? Isn't memory on a video card similar to that of memory used by your system?
 
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Yuriman

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Aug 27, 2002
Location
The OCFORUMS
You *can* lower the latency on your ram by flashing it with a new bios, but it almost always results in big lines across your screen, or extrene distortion. I cant think of a single instance where it worked, going up or down.
 

Ugmore Baggage

Member
Joined
Feb 12, 2002
ns is a measure of the chip itself. By the time you get to mhz/latency/etc you've taken the board into consideration. I suppose also the mhz rating is also a measure of the manufacturer's optimism.
the cchip is by far the main limiting component but you will see different manufacturers come up with different solutions for the other numbers. Generally the advertised mhz will be the same but the detailed numbers will differ and to some extent overclocking characteristics. Sometimes a manufacturer will take a chip and tweak it, making changes that will benefit from voltage mods etc. These chips might run faster than their recommended ns rating would suggest but might have horrible latency, etc. If you do the math and the ns and mhz don't match up then you probably don't want that ram (unless it's cheap and you don't plan to OC it on your own).

^^don't quote me on any of that^^

wannaberich, no none of that made sense. ns is a measure of time so low numbers are faster. PC rating is a measure of bandwidth so high numbers are faster. Your example has both numbers go in the same direction.
 
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wanna_b_rich_13

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Joined
Dec 15, 2003
Ugmore Baggage said:

wannaberich, no none of that made sense. ns is a measure of time so low numbers are faster. PC rating is a measure of bandwidth so high numbers are faster. Your example has both numbers go in the same direction.


Lets first make sure I am on the same page for the understandings. NS is the speed at which the memory will allow information to enter it, process, and pass out of it. Correct? The lower the number the faster the memory can do the algorigthms making it work quicker.

If what you are saying is true then how can a 512MB PC133 memory module @ CL3 and 5.5ns be changed to CL2 @ 5.0ns when running @ PC100 speed? This is an example of what you are saying that does not make sense. If this can be done on system memory then why not on video card memory?

I hope what I am saying isn't confusing anyone else.
 

JigPu

Inactive Pokémon Moderator
Joined
Jun 20, 2001
Location
Vancouver, WA
Sorta confusing, but I think I understand :)

System memory is normally measured using two numbers. Speed in MHz and Bandwidth in Mb/s. They very rarely use ns ratings, but I have seen a few that have advertised them. However, the ns ratings can be seen on the memory modules themselves sometimes.

Video card memory is commonly measured with two numbers as well. Speed in MHz and Cycle Time in ns. Memory is almost never measured in Bandwith on video cards. The ns rating can also be seen on the memory modules themselves.


What you need to understand is that the MHz and ns ratings are dependant on the underlying timings. When memory manufactures make memory, they "make" them for one particular speed. They stamp onto the chip the ns rating and tell the dude who assembles the chips into sticks what timings the stick needs to run at.

With system RAM, several MHz (and possibly ns) ratings are given. One for each timing they intend the stick to run at. However, if you look at the memory modules themselves, you find they're only got one ns rating. This is because even though they can run at the speeds and timings the stick is rated for, the module itself could have been put in many different things, and so a "standard" timing and ns rating was determined.

Whenever the module is used, the manufacturer tells the person who bought it what timings they should use. When they make system RAM, they use the default timings and speed as one setting. They also test it at a variaty of other speeds to come up with the other MHz/ns/CL ratings. With video cards, the manufactuer tells them the timings and they write them into the BIOS. The chip should thus run at the ns rating printed on the chip.


ns, like MHz is just a rating. It changes inversly with MHz. You can run a video card at a certian timing and speed (and thus change the actual MHz and ns it's running at), but you can never change it's rating. The module is rated for one timing, and even if it works at other speeds and timings, it dosen't change that printed rating.

...sorry for the long post :) I guess I wrote so much to be sure I answered your question :)
JigPu
 

eg1441

Registered
Joined
Nov 26, 2003
It's quite simple.


4ns = 4 nano-seconds which is 4 x 10^-9 seconds.

This is the time in between RAM accesses.


Therefore access rate =

1/(4 x 10^-9) = 2.5 x 10^8 s^-1

= 2.5 x 10^8 Hz (1 Hertz = "1 per second")

= 2.5 x 10^2 Megahertz
= 250 Mhz


"4ns" is simply a rating done by the manufacturer. They are telling you that the RAM is good for 250Mhz (500DDR).


You can also notice things like BH-5 is widely recommended overclocker's RAM. The 5 stands for 5 nano-seconds, meaning the RAM is certified by the manufacturer to run at 200Mhz (400DDR). Of course people regularly get their BH-5 to 250Mhz! so this certification is by no means a limit. The manufacturers just like to put conservative ratings on things... for obvious reasons.


Anyway, it's also of interest to compare normal RAM and video card RAM... normal ram is generally rated at 5ns, while video card RAM is rated as low as 2.8ns !! Quite a difference!!

Pity there's no BH-4 heh.
 
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wanna_b_rich_13

Member
Joined
Dec 15, 2003
Hmmm,

Thanks. I understand it now. So basically when you see a card manufacutrer making statments about the low ns speed of their memory it really doesn't mean TOO much but is still important.
 

Evnas

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Dec 14, 2002
Location
Seattle, WA
wanna_b_rich_13 said:
Hmmm,

Thanks. I understand it now. So basically when you see a card manufacutrer making statments about the low ns speed of their memory it really doesn't mean TOO much but is still important.

Its basically a reference what, on average, the chips can do. Of course there are ones that will perform better, and in some cases there are chips that will perform worse