Form Factor
Body
Side-Slider, Querty Keyboard, Touchscreen	Side-Slider, Querty Keyboard, Touchscreen
Dimensions
119 x 60.4 x 14.2 mm (4.69 x 2.38 x 0.56 in)	111 x 55 x 15.2 mm (4.37 x 2.17 x 0.60 in)
Weight
180 g (6.35 oz)	117 g (4.13 oz)
Build
Optical trackpad
Colors
Black	Black

Type
Display
S-LCD	TFT TouchWiz 3.0 UI
Size
3.7 inches, 39.0 cm² (~54.2% screen-to-body ratio)	3.2 inches, 29.1 cm² (~47.7% screen-to-body ratio)
Resolution
480 x 800 pixels, 5:3 ratio (~252 ppi density)	240 x 400 pixels, 5:3 ratio (~146 ppi density)
Multitouch
Yes
Protection
Corning Gorilla Glass

Alert Types
Notifications
Vibration, MP3, WAV ringtones	Vibration, MP3, WAV ringtones

Internal Memory
Memory
1.5GB ROM, 512MB RAM	160MB
Storage Type
	DNSe sound enhancement
Card Slot
microSDHC (dedicated slot)	microSDHC (dedicated slot), 1 GB included
Phonebook
Practically unlimited entries and fields, Photocall	Practically unlimited entries and fields, Photocall
Call Records
Practically unlimited	Practically unlimited

Operating System (OS)
Software
Android OS, v2.2 (Froyo)	Android OS, v2.2 (Froyo)
Upgradable
upgradable to 2.3 (Gingerbread)	upgradable to v2.3.6 (Gingerbread)
UI
Sense UI
Java
Yes, via Java MIDP emulator	Yes, via Java MIDP emulator
Browser
HTML, Adobe Flash	HTML
Messaging
SMS(threaded view), MMS, Email, Push Email, IM	SMS(threaded view), MMS, Email, Push Email, IM
Games
Yes	Downloadable

Chipset
Hardware
Qualcomm MSM7230	Qualcomm MSM7227 Snapdragon S1
CPU
800 MHz Scorpion	600 MHz
GPU
Adreno 205	Adreno 200
Sensors
Accelerometer, proximity, compass	Accelerometer, proximity, compass
Keyboard
QWERTY	QWERTY
Soft Keys
	2
SIM
Mini-SIM	Mini-SIM
Speakers
Yes	Yes
Navigation / Controls Keys
Optical trackpad	D-Pad
Audio Jack
3.5 mm	3.5 mm

Features
Additional Features
Dedicated search key Voice memo/dial Predictive text input	Document viewer

HTC Desire Z

Samsung Galaxy 551