How did PSP Slim loose weight compared to PSP?

Extensive testing and comparison between PSP and PSP Slim in the past few weeks have shown almost every single difference between the two. But a single question has not been answered in all that time of exploring new PSP Slim - How did PSP Slim, became so slim?

In our FAQ Roundup - PSP vs PSP Slim we explored functional differences between PSP and PSP Slim, and in our Technical specification comparison - PSP vs PSP Slim we have explored technical differences.

The guys from Nikkei Electronics Disassembly Squad were the first to deeply explore both PSPs from inside-out, and came to answers how did PSP Slim actually loose 33% of PSPs weight. Difference we’re talking about is 91 grams, 189 grams of PSP Slim compared to 280 grams of PSP. Big difference when it comes to handheld devices.

1. PSP Slim does not contain metal chassis
   Metal chassis which PSP contains, underneath liquid crystal module, is there to prevent damage to the device in case of dropping it, or twisting it. It increases the strength of the device, and adds significant 23 grams to it’s weight, whole 8% of total weight of it’s body.
2. PSP Slim has one layer of external chassis instead of two
   PSP chassis, even though plastic, have two layers. Internal carrying the most of the chassis, and external, which is molded to internal one - providing the exterior looks of the device.
3. PSP Slim has less electronic components inside
   PSP featured more chips and electronics which took on more space to accomodate. PSP Slim has less chips which do more, and take up less space. PSP featured WiFi with two chips and PSP Slim does the same with just one. PSP has micro-controller and separate chip for memory, PSP has just micro-controller with integrated memory. This difference has reduced the mass of PSP Slim with another 7 grams.
4. PSP Slim display is not so thick
   PSPs amazing display is just 4 millimeters thick, while PSP Slim features display which is thinner by 1.5 millimeters, not significantly thinner than displays used in newer cell phones. Difference in 1.5 millimeters was accomplished by thinner glass covering the display. PSP has glass thick 1.4 millimeters, and PSP Slim has glass cover just 0.6 millimeters thick.
5. PSP Slim has smaller - improved battery
   PSP has bigger battery which has some unused space in it’s curvature, but PSP Slim features smaller battery with improved circuitry, and less wasted space. New PSP Slim battery is also more durable to damage, due to added resin plate. What’s interesting is that PSP Slims battery is heavier than PSPs, even though it is smaller.

So when you add up the weight differences in the design and the interior of the devices, you can see that Sony had some compromises to make. PSP Slims weight comes at a cost, the device is not so durable as original PSP. Slimmer device chassis and removal of internal metal chassis make it more prone to damage. Not so thick glass over the display just render display even more vulnerable to external damage.

These five are key-points to PSP Slims lesser weight, you can read full four-page disassembly of PSP and PSP Slim here.