DDR3 SODIMM PC3-10600 vs PC3-10666

[daniel]

I'm looking to buy either of the following:

G.SKILL 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1333 (PC3 10666)
G.SKILL 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1333 (PC3 10600)

Both are the same, but one is 10600 and the other is 10666. What is the difference between these two RAM models? Everything looks the same (both are 9-9-9-24).

Also, if for example my laptop does not support 10666 but it supports 10600, if I buy the 10666 will this 10666 RAM automatically run at 10600 or will it show errors?

[GSKILL TECH]

It will show errors. Most laptops can support both, but some want one or the other. The 10666 is most common.

Thank you
GSKILL TECH

[benhase]

The reply above was incorrect

There is NO difference between 10600 and 10666 it's just a name the vender choose to call the RAM for marketing (people may think higher is better).
The basic clock for this RAM is 6ns (166.66MHz), multiply by 8 (DDR3 is 2^3=8, i.e. double three times) makes 1333.33MT/sec, multiply by 8 again (64 bit bus is eight bytes) and that's actually 10666.66 MB/sec. The official names is 10600 (rounded down), but various venders call it 10666, 10660, and even 10700.

http://www.tomshardware.com/reviews/...tout,1754.html

The "official" name for DDR memory is based on its bandwidth rather than clock speed. The easy method to convert data rate to bandwidth is to multiply by eight. Thus, DDR-400 is called PC-3200; DDR2-800 is called PC2-6400 and DDR3-1600 is called PC2-12800.

The math behind this conversion factor is simple: PC memory modules based on SDRAM technology use a 64-bit connection; there are eight bits in a byte and 64 bits equal eight bytes. For example, DDR2-800 transfers 800 megabits per pathway per second; its 64 pathways provide one eight-byte transfer per cycle and 800 times eight is 6400.

The problem comes with "rounding" and was first noticed with DDR-266 (PC-2100). The data rate of 266 MHz is actually 266.6 (continuously repeating decimal) megahertz, so the true transfer rate was 2133 MHz.

Today's DDR3-1333 has a peak bandwidth of 10666 MHz, which can be improperly rounded down and called PC3-10600, rounded up to be called PC3-10700 or stated without rounding as PC3-10666 depending on the manufacturer's desires.

Buyers will find that searching some venders for multiple DDR3-1333 brands will require them to check all three "ratings" to view modules of the same actual speed, but most brands label their DDR3-1333 products as either PC3-10600 or PC3-10666.

[Tradesman]

All three to do apply to 1333 sticks, some manufacturers use the different annotation to differentiate between sets that may be more tailored towards a particular chipset (often with laptops). And yes the 'official' label is PC3-10600 as laid out by JEDEC, which is slightly more common then 10666

[benhase]

Fast reply!

Just FYI, I recently purchased (Desktop Memory Model, Dual Channel Kit, 2x4GB) F3-10600CL9D-8GBNT (SODIMM is the laptop form-factor). It took me a long time to figure out 10600 would work with my Motherboard, which only listed F3-10666CL9D-8GBNT.

Wiki had the answer. http://en.wikipedia.org/wiki/DDR3_SDRAM
Both are Cas Latency: 9, Voltage: 1.5V, Timing: 9-9-9-24. Later (from online images) I figured out they both use the same chips. BTW, as expected, the memory works perfectly (G.SKILL rocks), thanks.

[Tradesman]

Glad to hear, makes for a good New Years gift! Have a gud 1 !