USB 3.0 faster than internal SATA

[Baked]

Setup is in my sig. I recently acquired a new larger SSD to store my games on. I had it connected to my system using a USB 3.0 docking station for the past few days, and got ATTO benchmarks of over 400MB for read and write. Today I installed that same SSD internally on the same onboard controller as my other two SSDs. Instead of seeing an increase in speed, I saw a decline. It's running at 300MB read/write now. I tried connecting it to the marvel 6GB port and it dropped the speed even more to 150MB read/write. WTF?!

 

[lamedude]

400MB/s (realistic USB3 speed according to spec)>300MB/s (SATA 3Gbps)
The Marvel SATA6 shares PCIe bandwidth with USB3 but it shouldn't be that slow unless you're using both at once.

 

[KentState]

Unless you are using an Intel SATA controller, all others will be inferior. Even the sub $200 cards typically do not perform well.

 

[Baked]

But that's the thing. I have a pair of SSD in RAID0 attached to the same controller (this is the onboard Intel controller that comes with the chipset), and it's doing 500MB!

 

[Hellhammer]

Your chipset (P55) only supports SATA 3Gbps so ~280MB/s is the max you can get from a single port (~550MB/s with RAID 0 using two ports). Marvell's SATA 6Gbps controllers, especially the old ones like yours, are just plain bad so 150MB/s doesn't sound surprising.

 

[Baked]

Cool, that makes sense now.