How to find your real GDDR frequency

Many people ask me how do I know the manufacturers frequencies for the GDDR in video cards. Actually it's not that difficult to find out so I thought of writing a small guide so I that I do not have to explain myself every time and also so that others can figure it out easily.

I have to give my thanx to GanGstaOne for helping in figuring this out.

How to figure it out

Every manufacturer of GDDR memories prints extensive information about the memory on the memory itself, this is usually in the form of a code made up of numbers and letters.


In the case of Samsung, the code will look something like this
K4XXXXXXXX-[Suffix]
The Suffix is usually just 2 characters, other times 4 or even more. But almost always, the last 2 characters of the code are the access time.


In the case of Hynix, the code is a bit different.
H5XXXXXXXXX-[XX]X
The [XX] is the access time code, so its not necessarily the last 2 characters. It is usually the first two characters after the dash.
On more recent GDDR the access time code is the first two characters of the second line (the line right below the long code on top).

In the case of Qimonda, its similar to the other two manufacturers but its a bit different for GDDR3 and GDDR5 memories (meanwhile, Qimonda went bankrupt).

Qimonda - GDDR2/GDDR3
HYBXXXXXXXXXXXX-[XX]
Again, the access time code is the number after the dash, the [XX] part in the code above. However, please note that this code may be just one character not two as it is usually for the other manufacturers.

Qimonda - GDDR5
IDGXXXXXXXXXX -[XX]
As above, the access time code is the number after the dash, the [XX] part in the code above.

I do not know any other method of finding this code besides having physical access to the memory module itself.

What is the access time/cycle time?

Simply putting is the fastest time at which the memories are designed to be accessed. This is calculated in ns (nanoseconds). This also means that the access time can be translated into the memory frequency and it is very easy to do this, just divide 1000 by the access time. (Example: 1.6ns means 1000/1.6 = 625 Mhz ). I won't go into details why it is calculated this way.

So now that you know where do find the access time code on the memory, here is a list of what each code means:

Code - Access time - Frequency for Samsung GDDR
25 --- 2.5ns ------ 400Mhz
22 --- 2.2ns ------ 450Mhz
20 --- 2.0ns ------ 500Mhz
19 --- 1.875ns ---- 530Mhz
18 --- 1.8ns ------ 550Mhz
16 --- 1.6ns ------ 625Mhz
15 --- 1.5ns ------ 650Mhz
14 --- 1.4ns ------ 700Mhz
12 --- 1.25ns ----- 800Mhz
11 --- 1.1ns ------ 900Mhz
1A --- 1.0ns ------ 1000Mhz
09 --- 0.9ns ------ 1100Mhz
08 --- 0.8ns ------ 1200Mhz
7A --- 0.77ns ----- 1300Mhz
07 --- 0.71ns ----- 1400Mhz
6A --- 0.66ns ----- 1500Mhz
06 --- 0.62ns ----- 1600Mhz
5C --- 0.56ns ----- 1800Mhz
05 --- 0.5ns ------ 2000Mhz
04 --- 0.40ns ----- 2500Mhz
03 --- 0.33ns ----- 3000Mhz
28 --- 0.28ns ----- 3500Mhz




Code - Access time - Frequency for Hynix GDDR
60 --- 6.0ns ------ 166Mhz
55 --- 5.5ns ------ 183Mhz
50 --- 5.0ns ------ 200Mhz
43 --- 4.3ns ------ 233Mhz
40 --- 4.0ns ------ 250Mhz
36 --- 3.6ns ------ 275Mhz
33 --- 3.3ns ------ 300Mhz
28 --- 2.8ns ------ 350Mhz
26 --- 2.6ns ------ 385Mhz
25 --- 2.5ns ------ 400Mhz
22 --- 2.2ns ------ 450Mhz
20 --- 2.0ns ------ 500Mhz
18 --- 1.8ns ------ 550Mhz
16 --- 1.6ns ------ 600Mhz
14 --- 1.4ns ------ 700Mhz
12 --- 1.2ns ------ 800Mhz
11 --- 1.1ns ------ 900Mhz
N0 --- 1.0ns ------ 1.0Ghz
N1 --- 0.9ns ------ 1.1Ghz
N2 --- 0.8ns ------ 1.2Ghz
N3 --- 0.77ns ----- 1.3Ghz
N4 --- 0.71ns ----- 1.4Ghz
N5 --- 0.66ns ----- 1.5Ghz
N6 --- 0.62ns ----- 1.6Ghz
N7 --- 0.57ns ----- 1.75Ghz
N8 --- 0.56ns ----- 1.8Ghz
T0 --- 0.5ns ------ 2.0Ghz
T1 --- 0.444ns ---- 2.25Ghz
T2 --- 0.4ns ------ 2.5Ghz
T3 --- 0.363ns ---- 2.75Ghz
R0 --- 0.333ns ---- 3.0Ghz
R1 --- 0.30ns ---- 3.25Ghz
R2 --- 0.28ns ---- 3.5Ghz

Code - Access time - Frequency for Qimonda GDDR (Qimonda went bankrupt at the beginning of 2009)
GDDR2/GDDR3
28 --- 2.8ns------ 350Mhz
25 --- 2.5ns ------ 400Mhz
20 --- 2.0ns ------ 500Mhz
16 --- 1.6ns ------ 600Mhz
14 --- 1.4ns ------ 700Mhz
12 --- 1.25ns ----- 800Mhz
11 --- 1.1ns ------ 900Mhz
10 --- 1.0ns ------ 1000Mhz
8 --- 0.8ns ------ 1200Mhz
GDDR5
32 --- 1.2ns------ 800Mhz
36 --- 1.1ns------ 900Mhz
40 --- 1.0ns------ 1000Mhz
45 --- 0.9ns------ 1125Mhz
50 --- 0.8ns------ 1250Mhz


Examples :

The memory of a Radeon 6970M:



The memory of 9800M GTX from a Clevo D900C/M570TU :




The memory of a 8800M GTX from a Clevo D900C:



The memory of a GT 425M MXM card (ASRock) - this is where Hynix writes its timings on more recent GDDR:



The memory of 8600M GS/GT GDDR2 (MXM types):



The memory of a 7800 Go:



Other cards:
ATI M4570: Laptop Forums and Notebook Computer Discussion (thanx to kiwitheiwik)

Why in the end the video card manufacture decides to use other frequencies than the ones specified by the memory manufacturer I have no idea... But I guess that this can give a helping hand in having a successful overclock of the memories.

Known GDDR frequencies:

If you have other pictures of GDDR memories would be great.

Card	Brand	Timing	Frequency	Supplier
Nvidia 680M	MXM Type 3.0b/ ?	04	1250 Mhz (x2)	Samsung
Radeon 7970M	MXM Type 3.0b/ ?	04	1250 Mhz (x2)	Hynix
Radeon 6970M	MXM Type 3.0b/ ?	04	1250 Mhz (x2)	Hynix
GTX 470M	MXM Type 3.0b/Clevo W860/870/x7200	04	1250 Mhz (x2)	Samsung
GTX 460M	MXM Type 3.0b/Alienware	04	1250 Mhz (x2)	Samsung
ATI M5870	MXM Type 3.0b/Clevo W860/870	04	1250 Mhz (x2)	Samsung
ATI M5870	MXM Type 3.0b/MSI GX740	05	1000 Mhz (x2)	Samsung
GTX 285M	MXM Type III /Clevo	1A	1000 Mhz	Samsung
GTX 280M	MXM Type III /Clevo	1A	1000 Mhz	Samsung
GTX 260M	MXM Type III /Clevo	1A	1000 Mhz	Samsung
Quadro FX 3700M	MXM Type III /Clevo/early Lenovo/early HP	11	900 Mhz	Qimonda
Quadro FX 3700M	MXM Type III /later Lenovo/later HP	12	800 Mhz	Samsung
9800M GTX	MXM Type III /Clevo	1A	1000 Mhz	Samsung
9800M GTX	MXM Type III /Clevo - D900C	12	800 Mhz	Samsung
8800M GTX	MXM Type III/Clevo	11	900 Mhz	Hynix
9800M GTS	MXM Type III /Clevo	12	800 Mhz	Samsung
9600M GT	MXM Type II/Clevo/Acer	12	800 Mhz	Samsung
ATI M 4670	MXM Type II/Acer	20	500 Mhz	Hynix
8600M GS/GT DDR2	MXM Type II	25	400 Mhz	Hynix
7800 Go	Clevo M59K	16	625 Mhz	Samsung

 

Nice guide, thanks for the response in the other thread and thanks for this guide as well, +rep.

 

Excellent guide. This is the stuff I like to see. Repped.

 

I updated the post with the 8800M GTX memory frequency.

 

thank you blacky

 

Now here's something worthy of a bookmark.

 

Last weekend I've check the memories of my video card and they are also 1A. I assume that all Clevo 9800M GTX ran with 1A timing as in 1 Ghz.

I've also got the chance to check out an 9600M GT from a Clevo M860 and it has 12 timings that 800 Mhz. The stock frequency for the 9600M GT so there isn't so much room for overclocking.
So I've updated the first post accordingly.

I've also found out something else but I will put that in a new thread.

 

Updated first post with new info on Hynix memories and some older 8600M cards.

 

Very nice blacky

 

Dang - now I wish my memory chips weren't covered by thermal pads - I'd love to find out exactly how fast my DDR2 VRAM is spec'd to go.
EDIT: Managed to find a pic of ONE 9500M GS MXM-II card over at LV2Go - definite Hynix memory, but the code's obscured by the camera angle. Looks like either 22 or 21 ns. No confirmation, though.