16mb vs 8mb cache?

[miro]

How much of a difference does a 16mb cache really make? I'm considering replacing my 120g with a sata 3gbps drive (probably a wd), and I'm wondering if the doubled cache is worth the extra money. I know it was a pretty big boost from 2mb to 8mb, but can I expect the same level of improvement going to 16mb?

For that matter, is there that much of a difference from sata 1 to sata 2, or ncq vs non-ncq?

 

[Bullitt]

yes, it offers a significant boost. Does it measure up to the difference from 2mb to 8mb? I dont think so, but if I'd have to say it will do 2/3's that feel for speed.

Another thing to consider is that the newer drives have higher platter density which helps out the transfer rates tremendously.

As it stands, right now is a nice time to buy some more storage space. The 250gb drives are at a nice price point (for me anyways) and $0.40/gig isnt uncommon.

The new WD drives as listed by Douglite is pretty much the best overall out there. Its not the absolute fastest, but its the fastest, quietest drive out there. I think the 300gb's are running ~$130.

Forget about the 3.0GB/sec sata, its marketing hype. In my priorities, I go with
Platter density, rotational speed, Cache, interface speed.

I'll grab a WD2500KS like Douglite has, I've come to similar conclusions, and agree with his take on the matter.

 

[DougLite]

Thanks Bullitt, now I'm going to go "inside the numbers" to explain why I like WD drives so much. Clicky SR performance comparison of four hard drives:

WD4000KD: 100GB platters, 16MB buffer
WD2500KS: 80GB platters, 16MB buffer
Deskstar 7K400: 80GB platters, 8MB buffer
WD3200JD: 107GB platters, 8MB buffer

Note that the Hitachi drive has far and away the best seek performance (nearly 1ms better on reads and 2ms better on writes than the two drives with 16MB buffers), but still cannot match the application level performance of the two 16MB buffer drives. The Desktar looks better in the Gaming DriveMarks, but still falls short of the high transfer performance and huge buffer on the 400GB WD drive.

WD3200JD and WD4000KD are of roughly the same density (100 vs 107GB platters, respectively), yet WD4000KD is able to blow away the desktop performance of the WD3200JD - by as much as 30%. The smallest gain is in WoW, with only a 10% improvement by going to a 16MB buffer. However, this stands to reason, as WoW stores its data in a handful of really large files, placing more emphasis on transfer rates than seek performance or buffer size.

Using this data, you should see a performance gain of 10-30%, depending on application, by going to a 16MB buffer. Checking prices on ZZF, the WD2500JD (8MB) is $111.50, while WD2500KS (16MB) is $118.99 - a difference of about 6%. Given that you will see a minimum performance boost of 10% and as much as 30%, 16MB is certainly a worthwhile investment.

You also asked about NCQ and 3gbps transfer (SATA-II if you know it by that name). Neither of these features make or break a drive, it's the buffer that is the biggest factor in desktop performance. Maxtor is able to increase desktop performance slightly with NCQ on, but WD and Seagate have not. Even with NCQ on, Maxtor still doesn't deliver the performance of WD's 16MB drives with NCQ off. As for 3gbps transfer, your storage subsystem is still limited by the mechanical parts of the drive at 1.5gbps, so 3gbps will only help you in a small percentage of burst transfers. Nice to have, but not a major factor in a buying decision.