Xenon: The Xenon was the first motherboard developed by microsoft back in 2005.

The Xenon motherboard is known for Overheating and other problems. Most often the problem is weak solder on your GPU. This is caused by overheating. The reason the GPU overheats is because the Heatsink is too small. (A Heatsink is like a cooler).

Pros:
1.The Xenon is the most popular Jtag as most of them were made before the NXE Dashboard, Therefore making them Jtaggable.
2.They also take type one Key Vaults so you have a better chance of Unbanning it.
3.Its also the easiest to jtag. All of it can be done above the motherboard.

Cons:
1.The Xenon will most likely Overheat within 4 months of buying.
2.It has a bigger chance of overheating if its jtagged as you would use it for 4 hours straight.
3.The Xenon also has its own Power Brick (203w) so you cannot use other Power Supplies with it.
4.The Xenon also does not have a HDMI port Zephyr:The Zephyr was the first HDMI console made back in 2006

The Zephyr motherboard is Identical to the Xenon. Same size heatsinks, Same CPU & GPU etc. Close to no difference with the xenon. It was the first HDMI console. It only takes Type 2 Key Vaults making it harder to Unban.

Pros.
1. HDMI Port
2. Most are Jtaggable because they were developed 2 Years before NXE Dashboard.

Cons.
1. Same as Xenon. It will overheat just has much.
2. Only takes type 2 Key Vaults

Falcon:The Falcon was developed in 2007 and had the first low wattage power brick at 175w

The Falcon motherboard was the big step up in Xbox 360s. The CPU Heatsink was made larger for easier cooling. The Console had a HDMI port. The Falcon was also the First Elite Console (Black). Although they added a larger heatsink to the CPU, it was mainly the GPU that was giving problems, therefore not making a huge difference. The Falcon also had the first low wattage power brick. 175w. The Falcon only uses Type 2 Key Vaults Making it harder to unban.. Also if you want to unban it you will need to have FreeBoot 0.030. The Falcon also introduced a 12v Fan. Unlike the Xenon and Zephyr that had a 5v

Pros.
1. Larger CPU Heatsink
2. More powerful fan
3. HDMI
4. First Elite Console
5. Less Energy Consumption

Cons.
1. Developed in 2007 so less are jtaggable
2. Only Takes Type 2 Key Vaults
3. Added a larger heatsink to the wrong processor
Opus:Non HDMI Console made in 2006 to replace Xenon boards that had red rings. Most are not Jtaggable. Very Rare Console. Had the Exact same motherboard as the Xenon Jasper:The big daddy. Made in late 2007-early 2008. HDMI Console. First arcade console.

The Jasper is considered the best Xbox motherboard. M$ added an extra Heatsink that connects to the GPU Heatsink. This made it almost immune to red rings. Jaspers come with 3 differents size NANDs. 16mb (Like all the rest of the boards) 256mb and 512mb. They only take Type 2 Key Vaults. These consoles were developed a few months before NXE so its hard to find jtaggablea. The Jasper is definitely the best motherboard for Jtags, But it very hard to find a jtaggable one.

Pros.
1. Almost Immune to Red Rings
2. Big Block NANDs
3. Extra Heatsink

Cons.
1. Only takes Type 2 Key Vaults
2. Extremely hard to find.
3. Very expensive if Jtagged