SDHC card is SLOW

I've got an 8gb class 6 SDHC in my pro, works great, for the most part. It's the 8gb card from newegg. It's supposed to be extremely fast, but I'm seeing the opposite.

Using the stock 1gb card that comes with the phone, I had about 200mb of stuff on it, and had enough space on internal storage, so I copied everything off... it was going at about 1700-1800 kb/sec... Not bad for the stock card.

I put in the new class 6 card, expecting better speeds. I copy back all ofmy files and what do I get?

120-140 kb/sec.

File transfers between internal storage and the card (both directions) are painfully slow. It took AGES to copy the files back.

It has continued to be slow, I tried the SD card tune up located in bigdiesel's signature... but it made zero difference. The card is so slow it's practically un-usable.

On the other side, if I enable disk mode on the phone, and copy files over USB, it's fast! 2000kb/sec is about what I see. I know the card is capable of faster, but the phone itself seems to have issues with data transfer speed over USB faster than that. I read that some place and they compared it to the blackberry storm which made 12mb/sec.

So, any reasons for the card to be so horribly slow when moving files between internal storage (or downloading from opera, or anything else for that matter).

Edit: It's slow on both the stock ROM, and Dream's ROM which I'm using right now. Was slow on Juggalo's ROM too (.05B)