Difference Between Memtest-86+ and Memtest-86 v 3.3

After suffering multitudes of BSOD's from Memory_Management error, IRQL_Not_Less_Or_Equal, PFN_List_Corrupt, Page_Fault_In_Nonpaged_Area,etc, I decided to download Memtest86 (in this case, Memtest86+ v1.70) Well I got thousands of errors with the original Samsung memory that came with my Dell XPS 410 (2X 512MB PC5300 DDR2 667Mhz): Pass 2: Test 7, Pass 3: Tests 4-6-7...over 19K errors. So, I pulled the sticks out and replaced them with Crucial memory I had recently purchased and ran the tests again. Pass 1: Test 7, over 5K errors. Well, I then downloaded Memtest86 v3.3 and re-ran the tests on the Crucial. after 5 passes, there are NO errors. I haven't yet re-ran the tests with the Samsung sticks, but my question is: Is Memtest86+ v1.70 a bad program? It is my understanding that Memtest86+ is a more advanced test, than Memtest86. I recently had my motherboard replaced by Dell because, I would get BSOD's continuously, no matter if I had XP or Vista installed. These BSOD's pointed to a bad Motherboard, so Dell replaced it (Bios on Board is latest) Thanks Kim Dell XPS 410 Intel Duo-Core E6600 (2.4 GHz) 1 Gig Crucial PC5300 DDR2 667MHz 16X DVD/RW Drive (Double Layer) PNY Nvidia GeForce 8800GTS 640 SoundBlaster XFi- ExtremeMusic Acer X241Wsd 24" LCD Monitor Software installed, Nvidia Driver 162.22 WQHL SoundBlaster XFi Vista Driver Mcafee VirusScan Plus 3DMark2001SE