RAM Speed & Timings for APU, serious inquiry

[MooseParade]

I've been searching for the last few days and haven't found a definitive answer. The question is all about RAM timings and basically is the more aggressive timings worth the price difference and will I (or the average user) see a difference in real world gaming & app / program usage?

The computer in question is a Toshiba L855D-S5114 Laptop

Specs:

AMD A8-4500M @ 1.9ghz (2.8ghz Boost)

AMD 7640G APU

4gb 1600 Single Channel

640gb 5400rpm SATA HDD

The rest I know is insignificant

I purchased the laptop for $379.99 from Best Buy which I think is a great deal for an A8. The problem is the RAM. I've done a lot of research that says that APU's more than anything benefit from faster RAM speeds and Dual Channel. I gathered a couple Dual Channel kits but again, the question arose in my mind, does the RAM Timing increase performance as much as the RAM Speed?

(All listings are 2x4gb Dual Channel Kits @ 1600mhz)

Mushkin Enhanced 11-11-11-28 $47.99

G.Skill 9-9-9-28 $51.99

Corsair Vengeance 9-9-9-24 $56.99

Is the increase in price equal to the increase in performance? Are RAM Timings that important for an APU?

[christoi]

Speeds and timing essentially go together really, as the timings state the amount of cycles that takes place for requested data to be delivered. Clock speeds increases the number of cycles per second and the timings state the amount of cycles to perform various operations (in a nutshell at least, more info here). Lower timing does lead to better performance, similarly to higher clocks. In that sense, CL9 memory at 1600mhz will perform like CL11 memory at ~1950mhz.

Between the timings however, I really wouldn't expect the difference to be that large. On the desktop platform there's a pretty noticeable performance difference with speed increases, but it's also worth noting that they are also notably faster. As memory speeds are pretty similar with both platforms however, I'd presume performance differences would be smaller with less of a bottleneck.

Single-channel memory probably would result in a large performance increase though, so I would recommend upgrading to the Mushikin. Don't think it's really worth going for the faster speeds to be honest, though given the price difference you could if you want ($430 for an A8 laptop is still a great deal anyways :)).

[Helltech]

Christoi, that is completely false about faster speeds. With APUs ONLY, not CPUs faster RAM actually results in much greater performance benefits, there is a large topic about this by TomsHardware.

http://www.tomshardware.com/reviews/memory-bandwidth-scaling-trinity,3419.html

[christoi]

Christoi, that is completely false about faster speeds. With APUs ONLY, not CPUs faster RAM actually results in much greater performance benefits, there is a large topic about this by TomsHardware.

http://www.tomshardware.com/reviews/memory-bandwidth-scaling-trinity,3419.html

What do you mean? I was talking in the context of APU's only...

[MooseParade]

I went ahead and pulled the trigger on the Corsair 9-9-9-24. I found it on eBay (from a high rated seller) for $49.99 with no tax and free shipping. I plan on running a few benchmarks before and after the upgrade to see what kind of impact it made on the CPU & APU.

[Wats]

I went ahead and pulled the trigger on the Corsair 9-9-9-24. I found it on eBay (from a high rated seller) for $49.99 with no tax and free shipping. I plan on running a few benchmarks before and after the upgrade to see what kind of impact it made on the CPU & APU.

That's at least 1866MHz right? Might need to learn to OC memory if it isn't.

[MooseParade]

No it's 1600.

[TechFan@ic]

With APUs RAM speeds are way more important than latency, so I'd personally take(OC) the RAM to 1866 and slightly raise the cas latency to 10, to prevent any strain on the memory module.

[MooseParade]

My laptop BIOS won't allow any form of OC'ing, that's why I got the fastest RAM I could find. I found one kit of 1866 9-9-9-24 for laptops and that was $88.99. I'll pass on that.

[christoi]

With APUs RAM speeds are way more important than latency, so I'd personally take(OC) the RAM to 1866 and slightly raise the cas latency to 10, to prevent any strain on the memory module.

Do you have a link/source of that? I've always thought that speeds and timings are dependent on each other, so I'm curious why there would be a difference in performance between the two.

[TechFan@ic]

With APUs RAM speeds are way more important than latency, so I'd personally take(OC) the RAM to 1866 and slightly raise the cas latency to 10, to prevent any strain on the memory module.

It's from personal experience & tons of reading, but I distinctly remember a review here they tested the same APU on 1866 CAS10 modules and 1600 CAS9 modules , the APU was faster on the 1866 modules.