Which RAM?

[StardogChampion]

I'm looking for some new RAM except I have no idea what the latencies mean - 4-4-4-12 or 5-5-5-18 etc.

Which is the best out of these 3?

http://www.overclockers.co.uk/showproduct.php?prodid=MY-108-CS&groupid=701&catid=8&subcat=813
http://www.overclockers.co.uk/showproduct.php?prodid=MY-064-GL&groupid=701&catid=8&subcat=813
http://www.overclockers.co.uk/showproduct.php?prodid=MY-066-GL&groupid=701&catid=8&subcat=813

 

[AtomicSpark]

Lower latency is better my friend!

 

[MRG]

Both Geil & Corsair make great RAM. Over the years I have had both in my systems. While i'm not all that sure about the overclock ability of either the Black Dragon or XMS2 series, I have had better luck with the Geil RAM when it came to overclocking. However, the Geil RAM listed does not have Heat Spreaders, so if you went with them, I would advise you buy some quality spreaders ASAP and install them yourself. I'm currently using 2GB of DC A-Data Vitesta. Excellent performance at stock speeds, but craps out after even a little overclock.

Another great company is G.Skill.

-MRG

 

[Boogaloo]

I would say corsair.

 

[AtomicSpark]

Now I have Corsair in my desktop now, granted it is a few years old. I would usually agree with the previous Corsair statement, but I'm starting to hear negative things about the Dominator serious as more "enthusiast" versions of RAM are starting to appear.

 

[DreamThrall]

From wikipedia:

When selecting a RAM card, the lower the CAS latency (given the same clock speed), the less time it takes to fetch data from it. If your application fits in the memory, lower latency can have measurable benefit. Due to the high premiums the lowest latency memories command, it's often better to use that money somewhere else such as higher RPM hard drive, more memory or higher clock speed processor/memory. Differences begin to be worthwhile at 3 CL units eg. CL7 vs CL4 so in otherwise up to date system it pays to pay more for better memory as well.

Comparing between clock speeds gets trickier. CAS Latency only specifies the delay between the request and the first bit. The clock speed specifies the latency between bits. Thus, when reading bursts of data, a higher clock speed can be faster in practice, even with a worse CAS Latency. For example, consider a 133 MHz CL3 device (7.5 ns per cycle, 3 cycles request latency) versus a 100 MHz CL2 device (10.0 ns per cycle, 2 cycles request latency). The first bit would be available after 22.5 ns (7.5 ns * 3) on the CL3 device and after 20.0 ns (10.0 ns * 2) on the CL2 device, demonstrating the benefit of a lower CAS latency. However when reading a burst of even 4 bits, the higher clock speed wins: 45.0 ns (7.5 * 3 latency + 7.5 * 3 bits after the first) versus 50.0 ns (10.0 * 2 latency + 10.0 * 3 bits after the first).

When a timing is specified for a particular CAS Latency (e.g. CL3 = 5.0 ns, CL2.5 = 6.0 ns), that indicates the clock speed at which that CL is supported. In this example, the RAM could support CL3 at 200 MHz or CL2.5 at 166 MHz. Most RAM supports multiple clock speeds, with varying performance, hence this notation.

RAM with a higher rating can be installed into a system with a lower rating. For instance: 200 MHz rated RAM can be installed in a system with a 133 MHz memory bus; however, the RAM will subsequently run at 133 MHz. The ratings are best understood as speed limits, rather than running speeds. Therefore, installing faster RAM into a system will not necessarily result in a performance gain.

RAM Timing

RAM manufacturers typically list the recommended timing for their RAM as a series of four integers separated by dashes (e.g 2-2-2-6 or 3-3-3-8 or 4-4-4-12 and so on). While there are many other settings related to RAM, these four integers refer to the following settings, which are typically listed in this order: TCL - Trcd - Trp - Tras

TCL = CAS Latency Time

Trcd = DRAM RAS# to CAS# Delay

Trp = DRAM RAS# Precharge

Tras = Precharge delay

The BIOS on a PC may allow the user to make adjustments to RAM Timing in an effort to increase performance or, in some cases, increase stability.

http://en.wikipedia.org/wiki/CAS_latency