I just got my M3 and have an a-data 4gb class 6 card. I have the exact same problem. Start of DoS and where on other games it flickers white on both screens, it just stops dead on white frozen. Also I've had several freezes just playing through the beginning of Portrait of Ruin. Usually when talking to someone and they are about to pop up a menu (such as wind and the shop keeper).
I took this benchmark using my cheap Dynex reader. The values seem low to me, but then I'm new to this.
SiSoftware Sandra
Benchmark Results
Device Index : 4053ops/minute
Endurance Factor : 94.70
Results Interpretation : Higher index values are better.
Performance Test Status
Run ID : Generic Mini SD Reader 4GB (USB)
Platform Compliance : x86
System Timer : 3.58MHz
512bytes Files Test
Read Performance : 32597ops/minute, 271.64kB/s, 1.81X
Write Performance : 3019ops/minute, 25.16kB/s, 0.17X
Delete Performance : 4832ops/minute
File Fragments : 1.0
Combined Index : 6504ops/minute
32kB Files Test
Read Performance : 14581ops/minute, 7.59MB/s, 51.84X
Write Performance : 2779ops/minute, 1.45MB/s, 9.88X
Delete Performance : 4853ops/minute
File Fragments : 1.0
Combined Index : 5092ops/minute
256kB Files Test
Read Performance : 3201ops/minute, 13.34MB/s, 91.05X
Write Performance : 1118ops/minute, 4.66MB/s, 31.80X
Delete Performance : 4388ops/minute
File Fragments : 1.0
Combined Index : 1728ops/minute
2MB Files Test
Read Performance : 433ops/minute, 14.43MB/s, 98.53X
Write Performance : 138ops/minute, 4.60MB/s, 31.40X
Delete Performance : 3376ops/minute
File Fragments : 1.0
Combined Index : 233ops/minute
64MB Files Test
Read Performance : 14ops/minute, 14.93MB/s, 101.94X
Write Performance : 6ops/minute, 6.40MB/s, 43.69X
Delete Performance : 557ops/minute
File Fragments : 1.0
Combined Index : 9ops/minute
256MB Files Test
Read Performance : 4ops/minute, 17.07MB/s, 116.51X
Write Performance : 2ops/minute, 8.53MB/s, 58.25X
Delete Performance : 125ops/minute
File Fragments : 1.0
Combined Index : 2ops/minute
Endurance Test Status
Operating System Disk Cache Used : No
Use Overlapped I/O : No
Test File Size : 32MB
Block Size : 512bytes
File Fragments : 1
Endurance Benchmark Breakdown
Repeated Sector ReWrite : 160kB/s
Sequential Sector Write : 690kB/s
Random Sector Write : 3kB/s
Drive
Total Size : 3.74GB
Free Space : 3.74GB, 100%
Cluster Size : 4kB
Opinions or ideas for solutions would be great. Thanks.