How much ram and flash are needed?

Hi guys and girls,

Lacking knowledge I hope you can help me...

On Aliexpress I found a lte modem/router with a ddr3 RAM memory of 256 Mbyte and a NOR flash memory of 16 Mbyte. If you pay extra it can be expanded to RAM 512 Mbyte and the flash memory to 32 or 64 MB.
I will use the device for streaming video on one or two laptops and perhaps record up to 5 cams to a nvr at the same time. Perhaps this usage is not related to RAM and flash. The only thing I think I understand is the flash memory is needed to get open wrt in the device.

Bigger flash means more future proof?
Is it worth the extra investment?

Thank you if you are willing to give your opinion!


Well it would help a lot if we would know what device you are talking about.
At least the price gap and the wifi speeds (better ofc SoC and Wifi chips) would be necessary to judge if it is worth. Assuming the device is supported by OpenWrt (I guess you have checked this already; there are not so much lte devices supported).

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16 MB flash is still good for almost all applications. If you're considering things that put large amounts of data in flash like adblock indexes, you'll want more than 64 MB.

The different flash sizes will require a different OpenWrt build, so check to confirm that a build exists for the variant you intend to buy. Larger RAM is usually automatically detected.

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Thanks a lot.

@pwned, on Aliexpress:
MTK MT7621 Enterprise Wireless Router Sata LTE 4G WIFI OpenWrt MT7603 MT7612 Gigabit MT7621A chipset Sim Card PCBA ODM OEM Board.
Changing flash and changing RAM cost € 10,- each.

@mk24 That's clear, thanks, I wiil stick to 16MB flash.


It would be more futureproof to pay the € 10,- for flash upgrade. Yes, 16 MB is currently still enough for most purposes, but 32 or 64 would be better, just in case. (4 years ago 8 MB was still enough and 8 years ago 4 MB was ok... :wink: )

Similarly, 256 MB RAM is enough now, but doubling it to 512 MB with € 10,- sounds also attractive.


So 20 bucks in total for both. If you want to keep the device for a longer period I would go for at least the flash upgrade. Like @hnyman wrote already. RAM is up to you. E. g.: If you want to run a really huge adblock list then RAM becomes very important.

Thanks, 20 euro is not a lot, but I'm happy to hear your opinions.

Besides, I'm surprised by the fast responses on this forum :smiley:!


Just to put this into perspective, one of the largest 'common' packages on a consumer router would be samba4 - this fits only barely into 16 MB flash device, so having headroom is always better. Likewise I wouldn't even consider less than 256 MB RAM anymore (this is really necessary for ipq40xx/ 2*ath10k devices, other wireless hardware could live with 128 MB RAM, but it shows where the limits are nevertheless), so having more would be really good.

Especially if you are buying in quantities of one (or <3, <5), it does make sense to go a little higher with the specifications, as long as the markup is reasonable, doing so will extend the usability of your device quite considerably and extend its useful lifetime.


Also anything that uses python will hardly fit into 16 MB flash.

Did have a look at all aspects of your answers. I will order the extra ram and flash..

Thank you all !

I will go ahead and say the complete opposite. RAM is more important than flash.

Why flash is not important? That device has sata port. You can configure it to use the sata drive as root. Even the tiniest sata drive would be more than enough to install all of the packages you need. Only the kernel will be present on flash. In that case even the 8mb would be fine. I would personally get the 512mb RAM / 16MB flash variant and get a 240gb SSD with the extra money.

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  • upgrading/updating an installation with extroot in place is not very convinient (esp. for beginners). same applies if you have to reset the device due to missconfiguration.
  • you would be limited in flashing your own builds including everything if larger then your 16MB flash.
  • you won't get a ssd drive for just 10 bucks (if it is is not from used market).
  • external drive is using ressources (cpu-interrupts, filesystem, etc.).
  • you are limited in device choice. not every device has esata. even those devices with usb 3.0 are limited in throughoutput compared to a flash device.

IMO just another level of complexity what can be avoided if you buy immediately the right stuff fitting your needs.

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It's really simple to do. Extroot configuration on the wiki explains everything a beginner should know.

Actually, a custom build would be much smaller because you would integrate required packages and fstab to the squashfs and don't have a jffs2 on the flash.

You can get an SSD for €20. Which would be the upgrade from 16mb to 64mb if every tier upgrade costs €10.

That's completely true and may be a legit reason for bigger flash.

Yeah, that advice is spesific to the device @Flymetothemoon chose. It just happens that the model he chose has sata port, otherwise I wouldn't recommended this.

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For ppl like you or myself it is. If I look into the forum there are a lot of ppl. relying on LuCI only and having difficulties with command line.

It highly depends on the device. I have serveral different and there are differences ~ 2MB in size ((packages are the same; because of firmware files for wlan). My own builds range between 13-16MB. I do not include spcial things (it is just a router). I'm just using full versions (dnsmasq, wpad, ssl).

Well 10 bucks which you do not need to spend. 64MB is plenty for a plain router.

O.K. I didn't know this for this specific device. But (personally!) I don't like it to mess around with an external device on a router. Don't get me wrong. I've used this for an older router already and it was nice to extend the 8MB flash to extend lifetime. But I would not do it if I would have the choice by buying a new device.


That's a very valid point. We don't buy a router everyday (well, most people at least), so if I am to buy a new one, saving few euros isn't really worth the hassle of setting up Extroot and go through complications in the future.

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Very happy with your conversation here :popcorn: :popcorn: :popcorn: It gives me a clue what OpenWRT is about.

I hope this device will give me a good 4g/lte reception. And at the same time a 5 GHz and a strong 2.4GHz wifi signal. This device has 3 PCie slots with witch I hope I can facilitate those objectives. Module MT7602E MTK MINIPCIE 11/b/g/n seems to have a somewhat stronger signal than average. I hope with Openwrt I can manage to use 2.4 and 5 Ghz at the same time and perform the 2.4 Ghz module at max strength. No special wishes,I hope.

To be honest, there is a chance, if things are working fine, I will simply forget to update the device...

Thanks everyone!

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