This post will be updated frequently with more latest news, stay tune.

Y500/Y400 with GT650m(GDDR5) phase out and GT750m(GDDR5) is coming soon to MY. 

Stock Ready:
Y400, i7-3630QM, GT750M(GDDR5)@RM2799, 4GB, 500GB, W8, red backlit, 120w psu, ODD (swappable), 2 yrs warranty
Limited stock

Coming soon
Y400(5937-3880), i7-3630QM, GT750M(GDDR5)@TBA, 4GB, 500GB, freeDOS, red backlit, 120w psu, ODD (swappable), 2 yrs warranty
Y500, i7-3630QM/GT750M(GDDR5))@TBA, W8, red backlit, 2 yrs warranty; ram/HDD/psu/ultrabay gt750m~TBA
RSP: Estimated around the same price as the old model with gt650m iff only upgrade gpu. 

Benchmarks from China:http://ideapad.it168.com/thread-3658952-1-1.html

It seems gt750m is an OC gtx660m with higher clock due to matured 28nm manufacturing.
GPUZ gt750m/Y400 vs gtx660m/Y580 vs gt650m/Y400

3Dmark11 with core i7, gt750m/Y400=P2937 > gtx660m/Y580=P2636 > gt650m/Y400=P2300.
3Dmark11 gt750m pawn gtx660m. 

3DMark11 with core i5, Y400/gt750m = P2649 vs Y580/gtx660m=P2450
http://ideapad.it168.com/thread-3659963-1-1.html

Furmark stress test for gt750m/Y400 vs gt650m/Y400 with default clock speed.
Default GT750m core clock 941mhz turbo boost to 1058mhz in Furmark test exceeded the default boost clock 967mhz  . This might be due to boost 2.0 in new Gpu.   
Default GT650m core clock 790mhz remains the same in Furmark test since GPU boost is not enable. 
GT750m temp increase to 55C with 1.1120V  compare to GT650m at 43C with 1.0250V.


New Z400 with GT740M in MY: 
Z400, i5-3230M + Nvidia GT740M@RM2099, 4GB, 1TB, W8
Z400T, i5-3230M + Nvidia GT740M + (1366x768, touch)@RM2399, 4GB, 1TB, W8; 2 years warranty
Z400T, i7-3632QM + Nvidia GT740M + (1366x768, touch)@RM2799, 4GB, 1TB, W8; 2 years warranty
Z400T, Pentium 2020 + Intel HD3000 + (1366x768, touch)@RM1699, 4GB, 500GB, W8

Y400/Y500 Malaysia official model with 2 yrs warranty.
http://bit.ly/rpZTBR
Y400(59-356819), i7-3630QM/GT650M(GDDR5)@2799/4GB/500GB/W8/red backlit keyboard/120w psu/ODD (swappable)/2 yrs warranty/backpack
Y500(59-364676), i7-3630QM/GT650M(GDDR5)/15.6" FHD@3799 /4GB/500GB/W8/red backlit keyboard/no ODD/2 yrs warranty
Free - Y500 GN36 - External Graphic / Removable
Free- Additional 170W(output 20V,8.5A) and 120W(output 19.5V,6.15A) AC Adapter

Y500/Y400 optional ultrabay components available according to Hikari85:
Idea Y Series Options
Y400 Removable DVD Burner DB35 RM190
Y500 Removable DVD Burner DB36 RM190
Y400 Removable HDD F450 RM450
Y500 Removable HDD F451 RM450
Y400 Removable Graphics GN35 RM580
Y500 Removable Graphics GN36 RM580
Y400 Removable Fan S2601 RM75
Y500 Removable Fan S2602 RM75
IdeaPad 170W AC Adapter (CE) RM229
[attachmentid=3349537]

Y500 review from notebookcheck 
http://www.notebookcheck.net/Review-Lenovo...ok.87585.0.html
[attachmentid=3316810]

pic & box identification for official local set Y500/Y400/Y580:
- SIRIM sticker is at the bottom of local set laptop
- Look for "MY" sign on the box, ie IDEAPADY500xxxxxxxxxxMY.
- make sure the spec same as local set listed above.
- make sure is the local set part No. stated on the box, ie Y580-part No. 59342479.
  Y500(59-349366 or 59-364676), Y400(59-356819). Refer local Lenovo site for any changes.
http://bit.ly/rpZTBR
- local set all come with 2 yrs international warranty
[attachmentid=3234780][attachmentid=3234782][attachmentid=3275619]

Y500/Y400 imported set (AP set)
Other variants of Y500/Y400 are US imported set(AP set) with different spec, cheaper price and 1 yr US warranty. Its best to avoid due to many potential hardware/warranty issues.
- read the threads on grey imported set warranty issues:
http://forum.lowyat.net/topic/2647407
http://forum.lowyat.net/topic/2619606
http://forum.lowyat.net/topic/2646366

- Major warranty claim issues on imported set((AP set) of Y580 face by unlucky forumer.
http://forum.lowyat.net/topic/2491914/+930
Case 1) Replied from Lenovo Malaysia in their facebook for the user who bought the imported set (AP set) quoted below:
Lenovo Malaysia:
"Hi Ms Radhika, sorry for the delay. I have intended to contact you as soon I was able to speak to the reseller who sold you the U300 but was unable to since their number was not reachable, however, in the process, dialled your brother's number which was written in the purchase invoice (thinking it could be the salesman's contact number) and I have spoken to him with regards to the management disposition on this case.

Lenovo management has decided that we will not be able to support your request for a replacement or refund because this machine is a US based machine. The dealer who sold you the unit is not an authorized Lenovo reseller. I have tried to contact the reseller but to no avail, in order to advise them the situation and for them to liase with you with regards to the solution that they may be able to offer you. I suggest that you walk in to the reseller's office if you also fail to reach them via telephone and bring up this issue to them.

Although Lenovo is an international company, the services that we render is subjected to the company's local policy and at the same time governed by Lenovo International Term & Condition.

For your existing U300 which are still at our service center, we will finish up the repair but there won't be any more warranty repair should any issue surfaces after this. "

Case 2). http://forum.lowyat.net/topic/2637513/+40

Reviews/ benchmark
Y500 i7+GT650M SLI+FHD reviews/benchmarks by our pro bro.
Thank you very much and credit to our pro reviewer/ benchmarker. 
Jabberwocky

myotgo

destroyer

23/11/12 update
Y500 benchmark from China  


-21/11/12 update
Y400 interior layout  & unboxing in China
http://itbbs.pconline.com.cn/notebook/15974545.html

Y500 unboxing in China
http://ideapad.zol.com.cn/60/160_592752.html

Unboxing of Y400 in youtube.
https://www.youtube.com/watch?v=jIElyWsVXZ4