Northbridge speed and low RAM timing significance on AMD platforms - Overclock.net - An Overclocking Community

Forum Jump: 

Northbridge speed and low RAM timing significance on AMD platforms

Reply
 
Thread Tools
post #1 of 63 (permalink) Old 02-05-2011, 03:54 PM - Thread Starter
Retired Staff
 
xd_1771's Avatar
 
Join Date: Nov 2009
Location: Vancouver, Canada
Posts: 20,615
Rep: 1027
Moved by luches's recent comparison, I decided to do my own round of comparison on NB speed vs. timings.

The rules/details of this article:
-Timings change between 6-8-6 and 9-9-9
-Northbridge speed changes between 2700Mhz and 3000Mhz
-Memory speed is constant 1600Mhz, the most optimal RAM frequency for AMD. This is not a RAM speed vs. timings comparison. There are no variances in this to keep everything fair.
-Everything else (bus clock, CPU clock, etc.) is also constant.
-The program used to test is "MaxxMem".

So, 20 minutes later:
1600Mhz 6-8-6, 2700Mhz northbridge:
27k6861final.png
1600Mhz 6-8-6, 3000Mhz northbridge:
3k6861final.png
1600Mhz 9-9-9, 2700Mhz northbridge:
27k9991final.png
1600Mhz 9-9-9, 3000Mhz northbridge:
3k9991final.png

1. Does a higher NB provide a benefit?
The answer is yes. You can see in both cases there's about a 500-600MB/s improvement when considering NB speed. Increasing NB speed is one of the ways to provide the biggest performance increases on AMD platforms.
2. Does higher NB speed provide more benefits over tighter timings?
Looks like the answer is also yes. At 3000Mhz 1600 9-9-9 I could whip up better MaxxMem results than at 2700Mhz 1600 6-8-6, so NB speed provides more benefits; of course I couldn't really prove what is equal and what is not (i.e. NB is 300Mhz higher is equal to how many timings lower?) but just so you know it can provide somewhat more benefit. Of course, do consider that you have 5-6ns more latency with CL9 vs CL6-8-6.
3. Do tighter timings still provide benefits?
Of course they will still provide good benefits on AMD. You can see the tighter timings provide a 400-500MB/s benefit in the benchmarks, and the latency is much lower.
4. So, in essence, NB speed and tighter timings scale about the same way?
Yes, so if you are running 1600 CL6 @ 2700-2800NB vs 1600 CL9 @ 3000Mhz NB, you get similar results +/- 100-200MB/s due to similar scaling patterns.
5. Which scales slightly better?
NB speed would scale slightly better over RAM timings/speed. So if you can get a higher NB speed but will have to slightly sacrifice RAM speed/timings, chances are you will get better bandwidth from this, but your latency will suffer.
6. Latency vs. bandwidth? Which is better?
I guess it really depends on what you do. On bandwidth intensive apps such as video editing, certain benchmarks, if you have an SSD, etc. the extra bandwidth provided would probably prove to be a lot better. However when you consider online gaming/ping, boot/app load times, etc. latencies would probably have more effect if the bandwidth is already fairly high. Remember, lowering timings can result in both extra bandwidth and latency. You may also want to look at individual values between different timings/NB speeds, i.e. read bandwidth vs. write bandwidth, depending on what you do.
7. Now what?
In conclusion both are significant and you should go for the highest NB possible and the lowest timings possible, because both give you the greatest results. Of course, lots of memory out there won't reach 1600 @ lower timings than just CL9, and lots of CPU IMCs out there (pretty much everything non-x6) won't reach 3000NB. So if you're looking for absolute best memory performance, these are the things to consider.

Notes:
-CPU speed appears to be around 1200Mhz, this is due to Cool'n'Quiet, something I can successfully apply to my CPU despite overclock.
-Actual CPU speed (during load) is 4.05Ghz in these tests.
-Tests were done on Windows 7 64-bit, on my "Benchmarking" user account which is separate from my main-use user account in that it does not have any startup programs, basic GUI, has more services disabled... basically, more suited for benchmarking.

Circumstances forced me to go inactive back in 2014. I guess I'm back for 2016, but won't be active much! Cheers!
Forum Rules (TOS) - Professionalism Initiative - News & info | New members - Marketplace
Good reads | VRM & MOSFET info - AMD VRM database - What unlocks? - CPU/NB/RAM multipliers chart


xd_1771 is offline  
Sponsored Links
Advertisement
 
post #2 of 63 (permalink) Old 02-05-2011, 03:58 PM
New to Overclock.net
 
Join Date: May 2010
Location: Montreal, Quebec, Canada
Posts: 3,372
Rep: 138
Blostorm is offline  
post #3 of 63 (permalink) Old 02-05-2011, 04:02 PM - Thread Starter
Retired Staff
 
xd_1771's Avatar
 
Join Date: Nov 2009
Location: Vancouver, Canada
Posts: 20,615
Rep: 1027
Thanks, I figured I'd create another thing worth stickying and maybe even prove some things for myself while I'm at it. I'm updating with more answers as I go, please tell me if I've missed anything wink.gif

Circumstances forced me to go inactive back in 2014. I guess I'm back for 2016, but won't be active much! Cheers!
Forum Rules (TOS) - Professionalism Initiative - News & info | New members - Marketplace
Good reads | VRM & MOSFET info - AMD VRM database - What unlocks? - CPU/NB/RAM multipliers chart


xd_1771 is offline  
Sponsored Links
Advertisement
 
post #4 of 63 (permalink) Old 02-05-2011, 05:44 PM
New to Overclock.net
 
MightyMission's Avatar
 
Join Date: Aug 2010
Posts: 1,632
Rep: 74
Excellent write up.i shall re read this again later to ensure it soaks in as i really struggle with ram and timings,i know this could sound silly ,but how do you get to cr1,is it down to performance ram or can you just enter it in the timings in the bios?and is it worth it if you have already caned the nb so much there is little space for any tighter timings?

MightyMission is offline  
post #5 of 63 (permalink) Old 02-05-2011, 05:54 PM - Thread Starter
Retired Staff
 
xd_1771's Avatar
 
Join Date: Nov 2009
Location: Vancouver, Canada
Posts: 20,615
Rep: 1027
Don't expect 1T command rate with most DDR2, it usually results in a small performance boost. Higher NB won't hold back or affect timings, unless you take the RAM speed up as well.

Circumstances forced me to go inactive back in 2014. I guess I'm back for 2016, but won't be active much! Cheers!
Forum Rules (TOS) - Professionalism Initiative - News & info | New members - Marketplace
Good reads | VRM & MOSFET info - AMD VRM database - What unlocks? - CPU/NB/RAM multipliers chart


xd_1771 is offline  
post #6 of 63 (permalink) Old 02-05-2011, 05:57 PM
New to Overclock.net
 
MightyMission's Avatar
 
Join Date: Aug 2010
Posts: 1,632
Rep: 74
Ahh yes because like i said i dont fully understand ram just yet,
so i let the ram speed rise and the latency fall of course with the increased nb and just up the ram volts,which is very lazy i know...
After re-reading this i will definitely have a tinker tomorrow with the timings and see what it gains.Cheers!

MightyMission is offline  
post #7 of 63 (permalink) Old 02-05-2011, 08:07 PM
 
Join Date: Sep 2010
Location: Australia
Posts: 2,529
Nice work XD, very helpful indeed +1,

Now I gotta work out how to get a higher NB OC on my asrock 890GX extreme 3.

I'm unable to change CPU NB voltage in my bios and can only change NB voltage.

The best I can seem to hit is about 2600Mhz on 1.4 NB Volt
(At about 3.6Ghz CPU clock = fail)

Any advice welcome

(sorry to invade your thread with a question XD, lol)
Casey Ryback is offline  
post #8 of 63 (permalink) Old 02-05-2011, 08:28 PM - Thread Starter
Retired Staff
 
xd_1771's Avatar
 
Join Date: Nov 2009
Location: Vancouver, Canada
Posts: 20,615
Rep: 1027
Maybe try a different BIOS? (i.e. newer one). I don't mind questions here either, I answer a lot of them as it is already anyway tongue.gif NB voltage is chipset voltage, don't believe it has anything to do with the NB/IMC on the CPU (which is controlled by the CPU-NB voltage).

Circumstances forced me to go inactive back in 2014. I guess I'm back for 2016, but won't be active much! Cheers!
Forum Rules (TOS) - Professionalism Initiative - News & info | New members - Marketplace
Good reads | VRM & MOSFET info - AMD VRM database - What unlocks? - CPU/NB/RAM multipliers chart


xd_1771 is offline  
post #9 of 63 (permalink) Old 02-06-2011, 02:32 PM
New to Overclock.net
 
raisethe3's Avatar
 
Join Date: Jan 2009
Location: Laguna Beach
Posts: 3,429
Rep: 134
Very nice XD! Always appreciating reading your great RAM info.

The Official MSI K9N2 SLI PLATINUM Owners Thread
|The Samsung Owners Club|-Mozilla Firefox Club|We Are Gr33n Machine|~Corsair PSU Fan Club~|~EVGA Fan Club~|Xigmatek Dark Knight Owners Club|**The Official Intel Core i5-2500K/i5-2550k/i7-2600K/i7-2700K Owners Club**|>>The Official ASUS P8P67/P8Z68 & P8Z68/GEN3 Series Owners Club>>|Intel 2500k, 2550k, 2600k & 2700k Overclocking Guide for ASUS
Main Computer
(15 items)
CPU
Intel 2550K 4.3Ghz
Motherboard
ASUS P8P67 EVO B3 (2103)
GPU
EVGA 8800GT
RAM
16GB ADATA DDR3 1600Mhz
Hard Drive
1TB WD Black (GAMING)
Hard Drive
1TB WD Blue (STORAGE)
Optical Drive
LG Internal Super Multi Drive 24X DVD+R
Power Supply
Corsair 650TX (Seasonic)
Cooling
Xigmatek Dark Knight S1283V
Case
ANTEC 300
Operating System
Windows 7 Ultimate 64-bit
Monitor
Samsung T220 HD
Mouse
logitech g pro
Audio
Superlux HD 681
Other
Samsung 840 EVO 250GB (OS)
▲ hide details ▲
raisethe3 is offline  
post #10 of 63 (permalink) Old 02-06-2011, 07:19 PM
 
Join Date: Oct 2010
Location: Los Angeles
Posts: 1,031
Yup, a high CPU-NB is the way to go smile.gif .
adamlau is offline  
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Overclock.net - An Overclocking Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off