So in preparation for migration of my quadcore Athlon II x4 620 2.6Ghz to my new AM3+ motherboard which should arrive any day now with the 8GB RAM and 128GB SSD, I ordered a AMD Athlon X2 4450B AM2 off of ebay for $10 to stuff the cheapest but fastest CPU I could find to install into my old motherboard which is Biostar MCP6PB M2+ so that this motherboard could still be used while I am building up the new system. Received my CPU in the mail yesterday just 3 days after buying it, and performed the swap last night. The good thing is that the Windows 7 activation didnt break and the motherboard was happy with the transition from the 2.6Ghz quadcore Athlon socket AM3 to the 2.3Ghz dualcore Athlon socket AM2 CPU.

But what I found interesting was that there was a 4450B and a 4450E CPU, and they benchmark with scores that are non similar. The 4450B benchmarks with a passmark score of 1266 as seen here http://www.cpubenchmark.net/cpu_lookup.php?cpu=AMD+Athlon+Dual+Core+4450B and the 4450E benchmarks worse with a score of 1043 as shown here http://www.cpubenchmark.net/cpu_lookup.php?cpu=AMD+Athlon+Dual+Core+4450e and they perform way different just by the difference of the slower performance 4450E with 2x 512k L2 Cache and the other better performance 4450B with 1 x 1MB L2 Cache shared among 2 cores.

At newegg as a reference, specs can be compared.
AMD Athlon X2 4450E ( 2 x 512k L2 Cache )
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103256

AMD Athlon X2 4450B ( 1MB L2 Cache )
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103263

Looking at the specs as to what B and E indicate, it appears that the B stands for "Business Class CPU", while there is no designation as to what E stands for but a guess is "Economical - Home User" The Value Build CPU = lesser performance @ lesser price tag.

On ebay among the many 4450E's this one was the only 4450B PRICED the same as the 4450E's, and I bought it thiking that maybe I would receive an incorrectly advertised CPU in which the seller probably has a 4450E for sale but accidentally listed it as a 4450B. Fortunately it is the 4450B better performing CPU and it runs quite well in my old motherboard for gaming.

To me I was kind of surprised that there was a letter attribute labelling the difference as for most of the AMD CPU's have always been totally different numbers or names to make the difference STAND out. And as far as INTEL goes the letter differences I have seen meant the difference between a Locked CPU (not intended for overclocking) and Unlocked CPU ( overclock at your own risk ), etc.

What really amazed me with these 2 CPUs with B and E is that its the same CPU but different L2 Cache configuration. Only other CPU's I have seen before like this are INTEL's in which a Pentium 4 2.8Ghz is 512k Cache and 533FSB and another Pentium 4 2.8Ghz HT 1MB Cache and 800FSB. In which the one without the HT stands out among the OTHERS with the HT hyperthreading designation.

My thoughts on these 4450E and 4450B is that engineering was testing to see whether 2 x 512k L2 Cache ( 512k per core ) would be better than 1 x 1MB L2 Cache shared among both cores and released both flavors of this same CPU model to cash in on both engineered and tested investments.

Anyone else seen similar like model CPUs with different Cache options before named the same with just a letter designation difference or is this a marketing ODDITY not to label it a 4450 and a 4455 ect?

That's fairly common with AMD actually. If you look at their older CPUs in particular, you'll see they have used the same model number (the Athlon X2 4800 is a good example) to refer to a lot of different CPUs, some of which use different sockets or cores. There was one that was actually a Phenom X4 in disguise, and you could potentially unlock its missing L2 cache, or even the disabled cores.
Intel tends not to reuse model numbers, back in the day you might have seen for example a Pentium 4 GHz on different sockets or with different cores, but then they moved the P4S onto model numbers like the Pentium 4 630 and that went away for good. Nowadays they all use different model numbers, with suffixes for example K indicating a derestricted multiplier, X indicating extreme edition (completely unlocked multiplier), T indicating low power, etc.