Because cost of production always goes down over time.  The margin of profit for the PS3 only grows with time, like all systems.  When the margin of profit gets large enough, it's followed by a price drop.  Over time the margin of profit grows again, and further price drops continue.  This is the cycle for almost ALL electronics hardware until it reachs EOL... Only Apple somehow has marketed itself in such a way as to just replace the product with a newer one rather than making the older one more attractive with a lower price point...  Apple is evil like this, lol

Ps4 wont save sony thats all you need to know

That's not really correct. It depends on the material costs, transportation costs, storage costs, etc. For example, If they only made 10'000 PS3s per quarter, making 10'000 cell processors for it would cost considerably more (per unit). It's an optimisation process between ordering material for x units, manufacturing y units, selling z units, etc..can become very complicated.

The main reasons for the rather large profit in the division have largely been mentioned: reduced r&d costs, not reducing PS3 prices, PS4 sold close to manufacturing costs, more online revenue. Let's not forget that MS was doing all the advertising for the PS4. The way MS floundered with their pr, and 180ed for months, saved a lot of advertising money for Sony....

Even with reduced manufacturing costs the PS3 is still down YoY for both hardware and software, so it's frankly incredibly unlikely for it to be responsible for the sudden jump in profits from 4.6 billion yen to 18 billion. The PS4 itself (the console) is sold at a slight loss, however it has brought in over 2 million new PS+ subscribers, along with several million game sales. Those following factors, especially the PS+ subs, are the most likely cause for the sudden big jump in profits.

Sure as hell aint the Vita :P

why r u so upset?

Lower manufacturing profits happen for everything but the games division had more than a 400% jump in profits. In order for your theory to make sense, Sony would have had to lower manufacturing costs of the ps3 by 400% and continue selling the same amount which is not true since the PS3s shipments were way  down. 

No. If you sell something for $200 with a profit of $5 and can lower the production costs from $195 to $175, the profit would rise from $5 to $25.

In this example, the production costs were reduced by roughly 10% with a profit gain of 400%

Mohasanie said  , they would have to lower costs by 400%  he should have said lowered cost enough to make 400% profit .

They can make some small profit adjustments by way of efficiencies , but because of the contracted nature of the business they would need a major hardware revision to make such a big difference and importantly in just one quarter, all things are possible but the fact that the increase came at a time where the  PS3 is losing ground and the Vita's treading water makes it a good bet that the catalyst is the PS4.

No he's right , take a 12month magazine subscription you have paid up front for 12 magazines this is usually called future benefit , and the sub revenue is commonly put down as unearned or deferred revenue and is denoted as a liability to sub revenue .

In the case of the mag sub this will change every month as the magazines are sent out .