Hello, from what I've observed from the comments of Y400 vs Y500
Sound -
Same quality, JBL speakers seems to produce a pretty high audio quality for a laptop.
Screen -
Different quality, Y500 has a Full HD screen (1920x1080) while Y400 has a HD screen(1366x768) only.
Keyboard -
Same quality, quite decent.
Trackpad -
Same quality, terrible trackpad but still usable.
As for battery runtime for 650m SLI for Y500, couldn't find one for Y400, here is the statistic from
checknotebook-Idle (without WLAN, min brightness):
4h 04min-Surfing with WLAN:
3h 10min-Load (maximum brightness):
1h 27minIf I remember correctly, the battery runtime will have additional 20% increase only without second GPU.
Considering, Y series does not support Optimus, the runtime is fairly high compared to other gaming laptop, however this is only achievable because the laptop GPU is throttled automatically to the point where gaming is impossible due to insanely low FPS when using battery.
Hope this info helps ^^
Thanks, and here I come, future Y400 user. ^^
Hope this monster won't disappoint me.