I have a WD black 6401aals drive which was supposed to be one of the faster blacks however both my seagate 500gb and my WD Blue 500aaks drives are much faster according to HD Tune. Here's the benchmarks. Faulty Drive?

Same UDMA mode?
Same Cable/SATA Port?

This was the same result on 2 different systems with old and then new sata cables. Fresh install of Windows 7 on one system and older install of 7 on the other.

Did it allofasudden get slow?

It's been this way since I got it but I blamed my old motherboard for the problem .. now that I got a new system and purchased 2 other cheaper drives for backup and run the benchmark again I see it's not my old system at all.

Run a different program like HDTach and see what the numbers are.

Same results with HD Tach. From the searches I have done I'm not alone with the same read results for this drive and they say when returned the drives were not defective. I see the black drive has an 11ms access time and the seagate and blue are 14 and 16 which leaves me wondering which drive would be better to use for an OS drive until i get extra money for a SSD? Is access time more important or would an extra 20-25 MB/s read even it out?

odd that ya mentioned that. After I got my ssd , for shitz I ran hdd tune to see the speeds.

a 500gb WD drive whipped the 74G raptor by ALOT. The rappy was averaging about 70-75Mb/s while this WD 500G drive was averaging 124Mb/s - figure that out.

Even my 2TB green drives would whip my old 74GB raptor in pure throughput (raptor only being SATA-I). I guess I could say the raptor is for sale, since I'll never have a need for it again.

something's definitely going on here.

in the laptop drive world i have a WD 320GB black and a WD 250GB blue. The blue gets about 75MB/s where the black gets about 65MB/s and both have about the same access time.
in the desktop drive world, my seagate 1TB and WD green 1TB drives both go about 85MB/s with roughly the same acces time (around the 16ms mark), yet the 160GB blue drive that is being used in my old system gets 102MB/s with a 13ms access time.

anyway, to the question about whether to go with the better access time or higher throughput, the answer depends on what you're doing. the faster access time will be able to load programs and boot faster where the higher throughput will be able to read/write sequential files faster. so it all depends on if you want faster file transfers or quicker load times.

Using HD Tune i get similar results as you

500GB BLUE=62.6 min/112 max/93.9 avg
500GB BLACK=45.8 min/91.4 max/75.2 avg

Intel SSD=153.9 min/228.3 max/213.9 avg(not in AHCI mode)

Yeah I guess I gotta gather up some more cash for an SSD for my system drive.

Now i have to find out why the blue is faster then the black.

Curious what you find out...

Yeah me too .. I can't understand why my blue is slower than my black. And we are not alone on this issue ether.