If 16GB is more than what you actually need then 2x 4GB
I don't know, while 8GB was once considered the 'sweet spot' of RAM (4GB was when Windows 7 was released in 2009), there's a lot more background tasks going on that soaks up RAM. Not to mention Google Chrome alone can use 8GB of RAM, have seen so in Task Manager numerous times.
If this were a year to 18 months ago, when RAM OEM's had jacked up pricing over one small facility (they tried to do what the HDD industry did 8-9 years ago), I'd say go with the minimum or buy used. In this day and age, 12-16 RAM is needed to cover the bases, to include whatever security apps are using. Usually, at least 1GB will be used by the hardware (audio/onboard video) alone. So 8GB won't go far, unless running 64 bit Linux.
As to the jacked up frequencies of RAM, I have to agree with you and others posting. There's little to be gained by running at 4400 MHz versus 3400-3600 MHz, in fact can cause instability & will require some voltage increase to maintain that level. This also leads to having to replace a MB sooner than normal, extra voltage means more heat & this is the bane of all electronics.
Purchase the amount of RAM needed for one's usage & go mild on the overclocking. Enabling XMP mode (AMD may call it another term, I believe on some boards DOCP) will (or should) automatically select the safe OC the RAM is designed for. By chance, just like CPU's & GPU's, if more is needed, then purchase higher frequency from the start. However, with DDR3 RAM, I couldn't really feel the difference between 1866 & 2400 MHz modules, I only purchased the GSKILL Trident X 2400 MHz kits because these were on promo ($99.99 per 16GB kit or 4 kits total for two Z97 rigs). This would max out the capacity of both, while having 2400 MHz kits for a total of $40 less than 1866 MHz ones.
However, my point being in the year of 2019, on a Windows machine, 8GB of RAM won't get the job done. If expense is a factor, then purchase used compatible set(s) on eBay, making sure the Seller has thousands of transactions with a score as close to 100% as possible. Due to pricing, I prefer eBay over Amazon. Both eBay and PayPal provides up to 60 days of protection for items at no extra cost, plus PayPal will reimburse any shipping costs for returns. However, it's not automatic, the receipt must be kept & any questions asked by PayPal must be truthful.