The phrase "a major difference when" is correct and usable in written English.
It can be used to highlight a significant distinction that occurs at a specific time or under certain conditions.
Example: "There is a major difference when comparing the results of the two experiments."
Alternatives: "a significant difference when" or "a key difference when".
Traditional basters are made of heat-resistant laboratory glass with a rubber bulb, but there are also basters made of clear or milky plastic or stainless steel -- a major difference when you want to know how much liquid has been drawn into the tube, and how clean the tube is afterward.
A major difference when comparing Couchbase with CouchDB regards sharding [10].
And while it does weigh less, it's hard to perceive a major difference when you're holding the two.
WinFrame allows users to use Windows applications off a server, without downloading the actual application, a major difference when compared with the network computer.
As it turns out, the 2G iPod Touch has an advantage of almost 100MHz over the rest of Apple's touchables, and that makes a major difference when you're talking games and almost certainly other apps.
While the decision whether to use O as a measure total or net evidence makes little difference to questions about the absolute amount of total evidence for a hypothesis (since O(H) is an increasing function of P(H)), it can make a major difference when one is considering the incremental changes in total evidence brought about by conditioning on new information.
Genetic data about the rs2229765 did not indicate any major differences when the population was grouped in five-year age brackets or split in the two groups (70 85) and 85+, but there was an increase of the A-allele in the males over 85, suggesting a sex-specific effect on male longevity.
Now more than ever I'm aware of the major difference when a Hollywood film is marketed as based on a true story, as opposed to being inspired by a true story.
In analysis stratified by education, an important confounding factor, we observed no major difference when evaluating breast-feeding categories (ESM Table 4).
For the Bordetella study a parsimony CGH tree has at least one major difference when compared to the available MLEE tree [ 39], the latter being an unreliable method as it only determines phenotypes and is not very reproducible.
Applying this philosophy to an in vivo experiment in a mouse brain shows major differences when taking steps to appropriately homogenize the beam.
