It's always interesting to see the full comparison between two graphics card, and including this article where we are going to show what a gamer can actually get from GT 730 DDR3 and DDR5 version on the following.
Technically, the difference in term of specification will give huge different between two product of video card. Even in same line of product, in this case a GPU where it's some common to find the product that provides two version, DDR3 and DDR5 especially on low entry market.
Yes the GT 730 for both version may look same since that different in price is not that significant.
If you don't have enough time to test such product, then simply see the YouTube to actually notice the different for the gaming performance, and many sites also do their own benchmark to test the certain card in their article.
Moreover, the effective memory clock from a DDR3 card is just twice, in this case, the GT 730 DDR3 is only rated at 1800 MHz.
Let's compare that with the DDR5 version where it can produce 4 times, and in this case, its memory clock is rated at 3600 MHz.
Not only for the memory clock aspect, the bandwidth speed is also different, and you can confidently guess which one is faster, even though both version has the same bus width, 64 bit.
There is the formula or calculation to count the amount of bandwidth, but let's ignore it since you can directly read it on AMD and NVIDIA site or Techpowerup site or on the vendor site like MSI, Asus, etc.
As you noticed previously, there are the difference on bandwidth speed and memory clock, but the base clock and bus width is technically same.
Basically with better or faster bandwidth and memory clock, a DDDR5 video card can actually show the better raw power for gaming performance in overall.
And in many maces, the difference in price is not too far, so when you have chance to find a GT 730 DDR5, then get it immediately over the DDR3 edition.
Moreover, if you want to save money and you don't really care about more performance then the DDR3 should be sufficient, otherwise, get the latter option.
Finally GT 730 in overall is not really good product right now even for 720p resolution, and just like GT 710, use the card only for games that were released many years ago, or use it only for 2D games and many casual titles.
see also: Top 5 Best Graphics Card Under 100 Dollars For Gaming