An In Depth DDR3 RAM Speed/Latency Log

[click4dylan]

Here are my results using maxmem at various speeds. Note that all these results were from fresh boots on windows 7 x64.

The ram i am using is 2x 2GB ADATA DDR3 1600 MHz 9-9-9-24 1.65V
and 2x 4GB ADATA DDR3 1600 MHZ 9-9-9-24 1.65V. yes they are mixed and matched with no problems. CPU is an i7 3770k @ 4.5 ghz

For the results in this log, all the ram was undervolted to 1.55V.

The log is pretty interesting in how command rate and timings affect the speed, and vice versa. The faster the ram speed is, the more 1T command rate makes a difference over 2T

	1600 MHZ 9-9-9-24-1T

	COPY		READ		WRITE		SCORE		LATENCY

	22592 MBPS	19836 MBPS	21184 MBPS	12.95 GBPS	61.5 ns
	22702 MBPS	20335 MBPS	21055 MBPS	12.95 GBPS	61.9 ns
	22592 MBPS	20551 MBPS	21159 MBPS	12.95 GBPS	61.7 ns
	22592 MBPS	20491 MBPS	20807 MBPS	12.95 GBPS	61.4 ns
	
AVERAGE	22620 MBPS	20303 MBPS	21051 MBPS	12.95 GBPS	61.6 ns

	

	1600 MHZ 9-9-9-24-2T
	
	COPY		READ		WRITE		SCORE		LATENCY
	
	20255 MBPS	12057 MBPS	13379 MBPS	12.72 GBPS	62.7 ns
	22702 MBPS	20390 MBPS	20978 MBPS	20.26 GBPS	62.5 ns
	22702 MBPS	19853 MBPS	21108 MBPS	20.06 GBPS	62.6 ns
	22592 MBPS	20280 MBPS	21160 MBPS	20.26 GBPS	62.9 ns

AVERAGE	22063 MBPS	18145 MBPS	19156 MBPS	18.32 GBPS	62.7 ns



	1600 MHZ 9-9-8-22-1T
	
	COPY		READ		WRITE		SCORE		LATENCY

	22702 MBPS	20519 MBPS	21058 MBPS	20.79 GBPS	61.7 ns
	22485 MBPS	20415 MBPS	20926 MBPS	20.67 GBPS	61.7 ns
	22592 MBPS	20415 MBPS	20928 MBPS	20.67 GBPS	61.6 ns
	22485 MBPS	20447 MBPS	20916 MBPS	20.68 GBPS	62.0 ns

AVERAGE	22567 MBPS	20449 MBPS	20957 MBPS	20.70 GBPS	61.8 ns


	1600 MHZ 9-9-8-20-1T
	
	COPY		READ		WRITE		SCORE		LATENCY

	22485 MBPS	20321 MBPS	21083 MBPS	20.70 GBPS	62.0 ns
	22485 MBPS	20489 MBPS	20934 MBPS	20.71 GBPS	62.0 ns
	22592 MBPS	20461 MBPS	20908 MBPS	20.68 GBPS	62.0 ns
	22592 MBPS	20364 MBPS	21110 MBPS	20.74 GBPS	61.9 ns

AVERAGE	22539 MBPS	20409 MBPS	21009 MBPS	20.71 GBPS	62.0 ns

	1800 MHZ 10-11-10-30-2T

	COPY		READ		WRITE		SCORE		LATENCY

	24348 MBPS	21215 MBPS	21419 MBPS	21.32 GBPS	61.9 ns
	24348 MBPS	21433 MBPS	21347 MBPS	21.39 GBPS	61.8 ns
	24100 MBPS	21569 MBPS	21440 MBPS	21.50 GBPS	61.9 ns
	24348 MBPS	21504 MBPS	21389 MBPS	21.45 GBPS	61.8 ns

AVERAGE 24286 MBPS	21430 MBPS	21398 MBPS	21.42 GBPS	61.9 ns

	1800 MHZ 10-11-10-30-1T

	COPY		READ		WRITE		SCORE		LATENCY

	24223 MBPS	21999 MBPS	21504 MBPS	21.75 GBPS	60.8 ns
	24223 MBPS	21910 MBPS	21442 MBPS	21.68 GBPS	60.9 ns
	24476 MBPS	22003 MBPS	21361 MBPS	21.68 GBPS	60.6 ns
	24348 MBPS	21987 MBPS	21346 MBPS	21.67 GBPS	60.7 ns

AVERAGE	24318 MBPS	21975 MBPS	21413 MBPS	21.7 GBPS	60.8





	1866 MHZ 10-11-10-30-2T

	
SYSTEM SHUTS OFF WHEN STARTING BENCHMARK

 

[ilovecats]

Some typos with the "9-9-9-24-1T" score? They all say 12.95gbps.

 

[click4dylan]

it was not a typo, maxmem might have a programmatical error that doesnt clear old values reliably

Edit 1: ill redo those tomorrow

Edit 2: haven't redone the other one yet but, i've found out that after 12 hours of windows uptime, the results plummet into barely 14000 MB/s of copy/read/write. anyone know how to fix this? i always leave my PC running 24/7 as a server and despise reboots.

after a reboot from those really low values, i received the highest scores yet:

	1800 MHZ 10-11-10-30-1T (SECOND REBOOT)

	COPY		READ		WRITE		SCORE		LATENCY

	25130 MBPS	22226 MBPS	21630 MBPS	21.93 GBPS	59.2 ns
	25130 MBPS	22415 MBPS	22093 MBPS	22.25 GBPS	59.3 ns
	24997 MBPS	22454 MBPS	21908 MBPS	22.18 GBPS	59.6 ns
	24863 MBPS	22221 MBPS	21787 MBPS	22.00 GBPS	59.4 ns

AVERAGE	25030 MBPS	22329 MBPS	21855 MBPS	22.10 GBPS	59.4 ns

 

[ChanceCoats123]

It's not a problem, it's the ram being filled with data from your applications. When you run the benchmark, that old data has to be cleared. If you do something called a "copy wazza" I bet you will get even better results.

 

[click4dylan]

unfortunately i had to drop it back down to 1600 mhz because the PC just randomly started shutting itself off for no reason