Netgear R6250 falsely advertised?

[Tomahawk]

I recently bought a Netgear R6250, and according to the box and the Netgear website it is supposed to have 256MB of RAM.

However, when I telnet into the router (courtesy of telnetable.py) and run 'cat /proc/meminfo' only 128MB shows up.

dmesg also reports 128MB of RAM. As does free, top, etc.

I could understand if each radio had its own integrated CPU with dedicated RAM, but my understanding is the R6250 is not like that.

So, my question is where's the other 128MB?

# cat /proc/meminfo
MemTotal:         125600 kB
MemFree:           66916 kB
Buffers:            4280 kB
Cached:            12320 kB
SwapCached:            0 kB
Active:             8824 kB
Inactive:          13452 kB
Active(anon):       5680 kB
Inactive(anon):        4 kB
Active(file):       3144 kB
Inactive(file):    13448 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:          5692 kB
Mapped:             2612 kB
Shmem:                 8 kB
Slab:              21260 kB
SReclaimable:       2008 kB
SUnreclaim:        19252 kB
KernelStack:         528 kB
PageTables:          428 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:       62800 kB
Committed_AS:      11980 kB
VmallocTotal:     647168 kB
VmallocUsed:       40344 kB
VmallocChunk:     589820 kB

# cat /proc/cpuinfo
Processor       : ARMv7 Processor rev 0 (v7l)
BogoMIPS        : 1599.07
Features        : swp half thumb fastmult edsp
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x3
CPU part        : 0xc09
CPU revision    : 0

Hardware        : Northstar Prototype
Revision        : 0000
Serial          : 0000000000000000

 

[stevech]

ARM7 CPU... old.

maybe 128MB is used for CPU heap, stack, variables, and another 128MB is used for packet buffers???

 

[Tomahawk]

ARM7 CPU... old.

maybe 128MB is used for CPU heap, stack, variables, and another 128MB is used for packet buffers???

I removed the heat sink covering the RAM. The part number silkscreened onto it is K4B2G1646E-BCK0, which indicate it's a Samsung 256MB DDR3-1600 module.

I'm still perplexed though. 128MB of packet buffer memory seems like an awful lot.

 

[thiggins]

From NETGEAR:

The R6250 has 256MB DDR3 memory. The current firmware utilizes 128MB memory, additional memory is for future upgrades for supporting additional features. Future firmware releases will enable the 256MB memory.

 

[stevech]

Nice, Netgear.
Market a 256MB product.
Hide the fact that half is ignored.

The glass-is-half-full perspective: I paid for the extra memory so that I'm ready when someday they'll have firmware that exploits that other half of the memory.

 

[Tomahawk]

From NETGEAR:

Thanks. I suspected as much, especially after I pulled the heatsink and saw the 256MB chip.

FWIW, while transferring files via FTP or SMB, top would show free memory drop down to 8-12MB with purges occurring often during sessions. I'm not sure sure how that effects performance versus utilizing the full 256MB of RAM, but I went ahead and returned it based on the principle of things.

Wireless transfer rates to an attached USB3 flash drive (NTFS) were decent though. With a N300 adapter, I was getting around 19MB/s and 16MB/s read and write speeds. Over wired gigabit, speeds were around 27MB/s and 19MB/s, but my ($99) RT-N65U easily beats it at 39MB/s and 23MB/s read and write to the same drive.

Unfortunately, I didn't have any .11ac adapters to test with.

 

[RMerlin]

ARM7 CPU... old.

maybe 128MB is used for CPU heap, stack, variables, and another 128MB is used for packet buffers???

This is actually dual A9s. ARMv7 is just the instruction set. So, not that old, A15 (the successor) is still quite recent. The BCM4708 was released last year by Broadcom.

BTW, that cpuinfo seems to be missing one core...