Android heap size on different phones/devices and OS versions

Question

Does anyone know if the heap size on Android phones is a constant value according to what is set in the OS version or if this is a setting which the phone producers can decide on?

Is the heap size proportional to the amount of RAM on the phone?

I've only found articles where people say that the heap size of an application is 16M. However, these articles are a bit old. From what I see, as an example, heap sizes vary from around 20M up to 24M on one specific model. This phone has 768M of RAM.

Answer 1

Some more device info extracted from build.prop files (adb -d pull /system/build.prop):

Phones (Android Version):

• HTC Wildfire (2.2.1) = 16MB
• HTC Wildfire S (2.3.5) = 20MB
• HTC Salsa (2.3.3) = 20MB
• HTC Desire (2.3.3) = 32MB
• HTC Desire S (2.3.5) = 32MB
• Sprd - Richview - S111 (2.3.5) = 32MB
• Samsung Galaxy S GT-I9000 (2.2) = 48MB
• Samsung Galaxy R GT-I9103 (2.3.5) = 64MB
• Samsung Galaxy Y GT-S5360 (2.3.5) = 64MB
• Samsung Galaxy Note N7000 (4.1.2) = heapstartsize=8m, heapgrowthlimit=64m, heapsize=256m
• Samsung Galaxy S3 GT-I9300 (4.3, xhpdi) = 8/64/256MB
• Samsung Galaxy S4 GT-I9505 (4.4, xxhpdi) = 8/128/512MB
• Google Galaxy Nexus (4.3) = 8/96/256MB
• Google Nexus 4 (4.4, xhdpi) = 8/192/512MB
• Google Nexus 5 (4.4, xxhdpi) = 8/192/512MB
• Samsung Galaxy S6 SM-G920W8 (7.0) = 8/256/512MB

Tablets (Android Version):

• Samsung Galaxy Tab GT-P1000 (2.2) = 48MB
• Samsung Galaxy Tab 8.9 GT-P7300 (3.2) = 5/64/288MB
• Samsung Galaxy Tab 10.1 GT-P7500 (3.2) = 5/64/288MB
• Samsung Galaxy Tab 3 10.1 GT-P5200 (4.2, mdpi) = 8/96/256MB
• Acer Iconia A500 (3.2.1) = 5/48/256MB
• Kindle Fire HD 7" (4.0.3) = 5/48/256MB
• Asus Transformer Prime TF201 (4.1.1) = 5/48/256MB
• Nexus 10 (4.4.3) 16/192/512 MB